If I might be so blunt, guitar is easy.
Because in its own unique way, the guitar offers us a lot of versatility in a simple format - the fretboard - which can be navigated in small, incremental pieces called intervals.
So those who understand guitar intervals - even in the most basic sense - will have a distinct command and control of their guitar.
They will know what to play, why they’re playing it and will likely never be at a loss for notes.
Guitar Education Resources I Use
I often refer to Guitar Tricks courses and video lessons, which to this point have amassed a library of well over 10k videos.
They're the best when it comes to online guitar lessons, and they'll let you try everything out free for 14 days. After that, you still have 60 additional days to cancel with a full refund, no questions asked.
You can checkout my full review of Guitar Tricks for more information.
Gear I used in this article
- PRS CE 24 Electric Guitar
- Line 6 Spider IV 150-Watt Modeling Amp
- Harmony: Its Theory and Practice (book by Prout)
That’s not to say they’ll never make a mistake or struggle with their instrument.
But a firm knowledge of intervals can limit those instances, by providing a tremendous amount of structure.
They’re the building blocks upon which chords, scales and all other note combinations are built. If we can learn those blocks everything else will make a lot more sense.
So this is the guide to understanding guitar intervals, in their proper context, and in a manner that’s optimal and useful to the guitar player.
But rest easy - you need not be a ranking music theorist to understand this material.
You just need to want to learn, improve and develop a foundational understanding of what’s happening on the fretboard.
If that’s the case, intervals are your best starting spot.
Music was my refuge. I could crawl into the space between the notes and curl my back to loneliness. ~ Maya Angelou
I often mention intervals in my writing and find myself wanting to link to an informational centerpiece that might explain them.
Such a place should be simple.
Because intervals are simple. They are useful and wonderfully helpful bits of knowledge; priceless to the guitar player. But I didn’t have – in my possession - such a resource to link to, nor was I able to procure one elsewhere - at least not that was straightforward and easy to understand.
So this article is meant to be that informational centerpiece for one purpose - to teach intervals.
That purpose is executed in three parts:
- Explain a theoretical topic.
- Lead to and present methods of application.
- Provide all information in the context of the guitar.
If you read through and practice the rest of this content, those three things are what you should expect to get in return.
If you’re still on-board, allow me to be more specific:
What I’ll Cover About Guitar Intervals
We’ll look at guitar intervals from three different angles:
- First: We’ll look at the basic definition of intervals and how to understand them in a formal and theoretical context. This is the “jargon” that you might hear in a music theory class, though in a more compact and succinct explanation.
- Second: We’ll look at intervals in chords, using seventh chords as our application and example.
- Third: We’ll look at intervals in the context of some of the most basic chords in existence - dyads and triads.
Making it through this material means you’ll have a complete and applicable understanding of intervals, so that you can use them for chord construction, modal patterns and to provide structure for all melody.
Let’s jump in.
Defining an Interval: Basic Definition and Music Theory
So what exactly is an interval?
We’ll look at two basic definitions:
You can download the PDF version of Prout’s book if you’d like to read further.
On the Guitar: The space between any two notes or points on the fretboard.
For example, the following tab is an interval:
E|-------- B|-------- G|-------- D|-------- A|-------- E|--3--5--
These two notes are separated by two semitones (which are also called “half steps” or one-fret jumps) which are equal to a whole tone or a “whole step.”
However, guitar intervals don’t always fall on the same string, as the following is also an interval:
E|-------- B|-------- G|-------- D|-------- A|-----3-- E|--5-----
Instead of falling on the sixth string - like the previous example - the second note falls on the fifth string at the third fret.
We’ll touch on this more later, but realize that even on different strings there is still a linear line of frets separating any two notes on the guitar.
1. What are the parts of an interval?
A musical interval is made up of two components:
- The Root Note: Represents the key of the particular pattern.
- The Interval(s): Any note(s) that correspond to a particular root are intervals of that root.
For example, a guitar chord is simply a collection of intervals attached to a specific root note.
Take the following C major chord:
E|----- B|--1-- G|--0-- D|--2-- A|--3-- E|-----
The root C is the root note at the beginning of the interval sequence (highlighted), while the other three notes are all intervals of the root C.
Intervals in chords are always understood in relation to the root note or the lowest note in a given key.
For instance, the open G in the C chord example is not the interval of the note that falls on the second or first fret. Rather it’s the interval of the C that falls on the fifth string at the third fret.
Because that C is the root of the entire chord.
2. Does an interval always involve only two notes?
Because any one interval can have only one root note and one interval note.
Now, there can be more than one set of intervals within a given pattern or chord (depending on how you might break it up), but you can’t have a single interval with more than two parts. It’s always just one note added to a root note.
It’ll make more sense once we look at some examples.
3. The Go-To Chart
There are a total of 11 different intervals before you get to your first octave, which doubles the frequency of the original note.
Therefore each interval should have a “Number of Frets” and an “Interval Quality.”
You’ll identify guitar intervals by associating the number of frets with the corresponding interval quality and vice-versa. Here’s a chart that displays that information for all 12 intervals:
The only thing we’ve omitted is an interval with 0 semitones, or essentially the same note played twice at the same time. This is simply called a unison interval, though it is not often mentioned or regarded as a common interval.
So how do we read this and translate it to the fretboard?
Let’s start with something easy.
4. A Simple Example
Say you were in music class and the teacher wanted you to draw a minor second on the chalkboard in guitar tab form.
What would you do?
First, you know from the above chart that a minor second is one semitone or one fret from the root. That means you’ll have a root note plus a note that falls one semitone from that particular spot.
So you’ve got plenty of options.
E|-------- B|-------- G|-------- D|-------- A|-------- E|--3--4--
In this example, the root note is at the third fret (G) and the interval falls at the fourth fret, creating one semitone of separation and giving us a minor second interval.
5. What about a major second?
To create a major second, we simply go back to our interval chart and figure out how many semitones we need to have separating our interval from our root note.
In this case, it’s just two.
You’re probably ahead of me by now.
Here’s our major second:
E|-------- B|-------- G|-------- D|-------- A|-------- E|--3--5--
You can continue through the chart in the same fashion.
6. Intervals on Different Strings
So how do we get situations where intervals land on other strings?
It’s harder to visualize, but what’s happening is the exact same process. Let’s use the major third interval as our example, since it’s one of the easiest to illustrate.
I’ll show you how to draw one up on a tab sheet with the two notes on separate strings.
What do we do first?
We can look to our chart (or memorize it - either way is fine) and see that there are four semitones that separate our major third interval from the root note.
So right away we could come up with this tab:
E|-------- B|-------- G|-------- D|-------- A|-------- E|--3--7--
This is a major third interval.
But there’s a problem. It’s a really long jump from the root note to the seventh fret, thus an inefficient movement.
And there’s a better way to play it.
If we know our fretboard notes, we can see that the note at the seventh fret is a B. To get a more optimal interval, all we have to do is find the same B on the fifth string.
E|-------- B|-------- G|-------- D|-------- A|-----2-- E|--3-----
That B falls on the fifth string - at the second fret - much closer to the root G at the third fret.
7. Compound Intervals
Know that you can identify any B note on any other string as a major third interval of the root G.
For example, the following highlighted note is also a B:
E|-------- B|-------- G|-----4-- D|-------- A|-------- E|--3-----
Technically it’s an octave higher, which makes it a compound interval, but you can still refer to it as a major third, with or without regard to the octave difference.
A compound interval is any interval that occurs after the intervals that fall between the root note and the first octave (simple intervals).
That’s a bit of a side note, but still worth banking in your memory.
Let’s move on.
8. What about the Perfect Fifth?
You might have heard the term “perfect fifth” before and noticed it on the interval chart.
This is an important interval to learn, as it forms one of the most basic power chord shapes in existence.
You’re almost certain to recognize it.
E|-------- B|-------- G|-------- D|-------- A|-----5-- E|--3-----
E|----- B|----- G|----- D|----- A|--5-- E|--3--
In this case we have our root G and the interval note D falling seven semitones above the root.
That seven semitone spread is what gives us our perfect fifth, making it an extremely common shape. And why is it called “perfect?” Music theorists have long used the term “perfect” to denote two intervals that sounded, and were considered to be, perfectly consonant.
For this reason a perfect fifth can also be referred to as the “consonant interval” or “highly consonant.”
9. What exactly does consonant mean?
In music, consonant always describes two notes that agree or sound complimentary when played together or close to one another.
It’s derived from the audible dichotomy between consonance and dissonance.
These terms are difficult to properly define, though can be generally thought of as opposites, where consonance is considered stable and dissonance is considered unstable. It is essentially based on the perception of unity or cohesiveness between two notes.
You can have both perfect consonances and imperfect consonances:
- Unisons and Octaves
- Perfect Fourths and Perfect Fifths
- Major Thirds and Minor Sixths
- Minor Thirds and Major Sixths
Note that you can memorize, understand and use the perfect fifth without fully comprehending the idea of a consonant interval.
I suppose you could think of that topic as extra credit, and not crucial for real-world application.
Transitioning to Application
We’ve been looking at intervals in terms of their theoretical definition.
So now you should know what intervals are and how to explain them using formal, conceptual language.
You’re ready to take this knowledge and apply it to the fretboard. Our approach will be a two-lane road:
- We’ll continue to look at music theory as it pertains to basic guitar chords.
- Second, we’ll apply what we already know about intervals to things we do on the fretboard.
Once you’ve done this you’ll understand intervals not just in theory, but in a practical sense, having seen how they can actually help you.
We’ll look at understanding intervals in the context of seventh chords, dyads and triads.
Understanding Intervals by Studying Seventh Chords
Have you ever wondered what a seventh guitar chord actually is?
What does that number mean?
Or what about the theory behind seventh chords? How does it all work?
These are questions you’ve probably asked yourself before simply memorizing the chord and moving on. Still, you continue to think, “Isn’t there a better way to learn this outside of note-by-note memorization?”
And the answer is yes - there is a better way to learn.
In fact going a little deeper with this topic, will show us a lot about intervals and music theory in general.
A Better Way to Learn
Because of the way my brain is wired, I’m intensely pragmatic and skeptical.
As a result, I tend to look for ways to understand music at a deeper level and “connect the dots,” so to speak. That’s what we’ll do here with seventh chords.
Instead of just memorizing them and learning the fingerings, we’re going to learn how to build them from the ground up.
In so doing we’ll learn about the purpose and function of intervals.
To understand seventh chords you have to first understand the basic underpinnings of what a chord is and what a triad is.
We’ll consider both of the following:
- Formal Definition of a Chord
- Formal Definition of a Triad
Once we’ve covered those two concepts, we can responsibly define and study seventh chords.
10. What is a chord?
Conventionally a chord is a combination of three or more notes, heard either simultaneously or in succession like an arpeggio.
Webster’s Dictionary defines it like this:
Three or more musical tones sounded simultaneously.
In contrast, Ottó Károlyi, a senior music professor at the University of Stirling, recognizes two or more notes as a musical chord.
Two or more notes sounding simultaneously are known as a chord. Károlyi, Otto (1965)
I tend to favor Károlyi’s definition and hold that two notes or more should be considered a chord. However, both are valid explanations.
11. What is a Triad?
Formally, a triad is a chord made up of three notes which are successive third intervals.
But what does that mean?
Well, we’ve got three notes to work with. And we know that one of them, the lowest one, will be the root note, while the others will be corresponding intervals.
The next note will be a third (either major or minor) from the root note, while the last note will be a fifth (diminished, perfect or augmented).
So a triad includes:
- A root note.
- Third interval (major or minor) from the root note.
- Fifth interval (diminished, perfect or augmented) from the root note.
Take the following major triad example:
You’ve got your root, which is easily identified as your lowest note. Then your major third which is four semitones away from the root. So if you were to start at the root note and count up the fretboard four frets, that note would match the one at the third fret on the second string.
We saw this earlier in our major third example from the first chapter.
Same goes for the perfect fifth, which is seven frets (semitones) from the root note.
Visualize the process by simply counting up from the root note on the same string.
You can see that the note occurring four frets up from our root note (on the fourth fret) is a C, which means we can use the C on the fifth string at the third fret to begin the construction of our triad.
This is our formal definition of a triad.
But there’s a more casual way to explain it as well, with some lingering authority.
The Casual Definition of a Triad
20th Century theorists, Howard Hanson and Carlton Gamer, expanded the term to make room for essentially any group of three notes, or pitches, that are combined for a chord.
This gives us both a formal and casual definition.
Here’s a graphic to help memorize each one:
Though it’s true that Hanson and Gamer’s definition is valid and easier to digest, we need to be aware of the formal definition of a triad in order to understand the interval structure of seventh chords.
Up to this point, we’ve prioritized a baseline understanding of chords and triads in a general sense, having yet to look at any actual seventh chords.
But now, the foundational information has been covered and we can finally get to a seventh chord definition.
12. Defining Seventh Chords
Unlike our previous two definitions, there’s little room for interpretation when it comes to determining what a seventh chord actually is.
Note that the formal definition is exclusive.
A seventh chord consists of a triad plus one more note that forms a seventh interval with that triad’s root note.
If you understand intervals and triads, it’ll be easier for you to construct a seventh chord as well, because we’re simply adding one more note to an established triad.
It becomes a matter of simply counting intervals.
Take the following seventh chord for example:
You’ve got a root note, major third, perfect fifth and a major seventh that come together to form a basic major seventh chord.
And we can get there entirely by counting intervals from the root note.
Now up to this point we’ve only used major triads for our examples.
There are five other common or “Tertian” seventh chords that we’ll cover to make sure we know the process and the way they’re constructed.
- Major Seventh
- Minor Seventh
- Dominant Seventh
- Diminished Seventh
- Half-Diminished Seventh
The process is the same for each type of chord – simply build each chord starting with a root note, then add a third, fifth and seventh interval.
I’ll give you the interval pattern for each chord, since all of them have different interval sequences. If you prefer, those sequences can be viewed via the seventh chord wiki page.
13. Major Seventh Example
We’ll go ahead and build out our major seventh chord on guitar tabs.
Remember, all we need to start is one triad.
Start with this major triad shape.
By now it should be fairly easy for you to spot the root note, third interval and fifth interval in our triad. Remember, it’s still a major chord, so the intervals for our major seventh chord will have the following qualities:
Major Third - Perfect Fifth - Major Seventh
If you memorize this, you can create a major seventh chord with any root note of your choice.
So all you’ve got to do now is add the major seventh interval.
Where do you think it would go? How could we figure it out?
Remember that a major seventh interval is 11 semitones from the root note. So we can simply count from the root note on the fourth string at the fifth fret, all the way up the fretboard.
If you do that you’ll go from the fifth fret to the 16th fret.
That means we’re looking for an F# near our original chord. The first note that comes to mind might be the low F# on the sixth string, but that’s not a functional option.
However, the F# on the high E string is in perfect position to complete our major seventh chord.
You can apply the same process to any other triad to make it a major seventh chord.
Notice how knowledge of intervals becomes increasingly crucial.
14. Minor Seventh
All of the same principles will apply to the minor seventh chord, where the only difference is that third and seventh intervals will be minor in their relation to the root note.
Here are the intervals we need to use.
Minor Third - Perfect Fifth - Minor Seventh
We now have our root note on the sixth string at the fifth fret, meaning our chord is going to be an Amin7 by the time we’re finished.
Our first interval is a minor third which is three semitones from the root.
The perfect fifth interval is the same as before, now falling on the second string at the seventh fret.
In order to add our minor seventh interval, we need to count ten frets up from the root note.
This gives us a G, which we can include in our chord with the G note at the eighth fret on the second string.
15. Dominant Seventh
A dominant seventh chord will be composed of a root, plus the following intervals:
Major Third - Perfect Fifth - Minor Seventh
Let’s start with an E at the seventh fret on the fifth string.
Our major third and perfect fifth should be easy by now, leading us to the following shape:
Now we need to add our minor seventh, which will be a D note, considering our root E.
The seven, highlighted in red, is our D note, completing the dominant seventh chord.
16. Diminished Seventh
Figuring out the diminished seventh will be slightly trickier because you’ll have two diminished intervals to deal with.
Minor Third - Diminished Fifth - Diminished Seventh
Our diminished fifth (also know as a Tritone), is going to be six semitones from the root note or one less than what we were becoming accustomed to with the perfect fifth.
The sound it creates is dissonant, which you may recall we mentioned earlier is simply the opposite of consonant.
In order to add our diminished seventh note, we’ll need to go nine semitones above the root note, which in this case is A. 10 semitones would get us to G, so one less will be F#, which we’ve highlighted red in our chord.
17. Half-Diminished Seventh
The half diminished seventh requires the following three intervals from the root:
Minor Third - Diminished Fifth - Minor Seventh
So this chord will actually be a bit easier to understand than the diminished seventh, since we have two minor intervals instead of two diminished intervals.
We’ll start with our root note here:
Remember that a diminished fifth is six semitones above the root.
Now we can add our minor third and seventh intervals.
The same principles can be applied to the minor major seventh chord and the augmented major seventh chord, which are not listed here, but are still considered Tertian. As long as you know the intervals, you’re good to go.
Want to see them all in one place?
Here you go:
Major Seventh: Major Third - Perfect Fifth - Major Seventh
Minor Seventh: Minor Third - Perfect Fifth - Minor Seventh
Dominant: Major Third - Perfect Fifth - Minor Seventh
Diminished: Minor Third - Diminished Fifth - Diminished Seventh
Half-diminished: Minor Third - Diminished Fifth - Minor Seventh
Minor Major Seventh: Minor Third - Perfect Fifth - Major Seventh
Augmented Major: Major Fifth - Augmented Fifth - Major Seventh
If you know the intervals you can discern and even build your own chords pretty quickly. So instead of looking up a bunch of seventh guitar chords and simply memorizing, you can make them from scratch.
Pretty cool, right?
Instead of having a surface knowledge and not really know what you’re playing, you know why every single note in these chords exists, namely because you know the four components that make up a seventh chord and the properties of each interval.
Let’s go ahead and review:
- Third Interval
- Fifth Interval
- Seventh Interval
It’s not easy, at least not for the average music student.
But most things worth learning, like music theory, aren’t easy.
If you commit to learning the process and giving it time, all this stuff will become second nature.
18. The Process
That process is critically important because it’s repeatable.
Instead of memorizing the actual chords, we’ve memorized the mechanism by which we get to any chord.
So for easy memorization of the process:
- Understand the basic definition of a chord.
- Understand the definition and formal components of a triad (root, third and fifth interval).
- Learn how to count intervals from the root notes (by the number of semitones - use the chart provided).
- Build your seventh chords by finding a root note and adding the appropriate intervals depending on the commons name (major, minor, diminished, etc.) of the chord you want.
Easier said than done, but it’s all there.
And once you learn it, you’ll be ahead of most who just rely on raw chord memorization - with no interest in music theory - to get by.
Simple Guitar Chords: Dyad and Triad Theory
I mentioned that we would be using dyads and triads to illustrate our chords and apply our intervals.
Dyads and triad (which we’ve already covered in part) are the next step above intervals in terms of fretboard building blocks. They’re the simplest and most basic guitar chords you can learn.
We define the two types of chords this way:
- Dyad: A chord made up of only two notes - a root note and one interval.
- Triad: A chord made up of three notes - a root note and two intervals.
Though the theory gets more involved, we can start with this basic understanding of our two chord types and go from there.
We’ve already covered triads, so let’s focus on dyads.
We’ll say that a dyad is any interval that can be interpreted as reasonably consonant.
Let’s look at some examples.
19. Basic Dyads to Start With
We want to start simple, so we’ll look at two different types of dyads, which are distinguished by the interval of each chord.
- Major Fifth Dyad
- Octave Dyad
So the distance between the root note and the second note in the chord will determine what type of dyad it is just like in any interval that we might use.
Major Fifth or “Perfect” Dyad
A major fifth is the term used to designate one such interval, which is seven frets away from the root note. Here’s the tab.
I’ve chosen to put my root note on the fourth string at the fifth fret, but you can start this root note on any fret on either the sixth, fifth, fourth or second string and play the same configuration.
The note at the seventh fret is a perfect fifth and the only note that accompanies the root.
This is your first, basic dyad.
An octave dyad looks almost the same, except our interval is one octave higher than the root note, which means it’s the same note at a higher pitch.
Here’s the tabbed example.
D Major Dyad Shape
The major sound you get from the basic shape of a D chord is also a moveable dyad.
We omit the root D and instead allow the A at the second fret to function as our root (or we assume the root D as a ghost note). If we move the note at the third fret (D) up to the fifth (E), we have another useable dyad.
Again, a perfect fifth:
20. Triadic Chords
There are a lot of different ways to configure a triadic chord, though most are simply an expansion on commonly used dyads. For example, if you take the D major dyad shape we just covered and add the root note, you get a fairly common triadic chord with a D root.
To transpose the chord to a new fret, simply move the root note to the desired key.
Commonly Used Major and Minor Triadic Chords
There are a lot of different chords that are made up of three notes. We’ll give most of these chords in the key of C, though keep in mind they can be moved to any fret.
Like dyads, each chord form is signified by a collection of intervals and octaves.
In many cases, a triadic chord can be a stripped down version of a more commonly known open chord. Take the open C major for example.
We have four notes here, but we can omit the highest one on the first fret (C) since we’re already getting a C from the root note on the third fret.
Now our triadic shape looks like this, and we can more easily move it to other frets:
Thus, if we transpose the root of the chord to the fifth fret, we’d get the following shape:
Try picking through each shape one after another.
Let’s look at a few more triadic shapes.
The Power Chord Triadic Shape
One of the most frequently used chords would be a power chord made up of three notes.
The first is the root note, followed by a perfect fifth interval and then an octave of the original root note.
This chord can be easily moved and can work with a root note on either the sixth or fifth string.
You can change the interval of the chord (the note in the middle) if you want to give the chord a different tone. Instead of adding a perfect fifth, add a major third, which will fall on the seventh fret.
The Major Barre Chord Triadic Shape
If you start a barre chord with the root note on the fifth string, a typical major shape will look like this.
If we omit the root note and the high G on the first string, we get a nice triadic chord where the root is a ghost note or assumed (C in this case).
This chord can be easily barred with one finger. You can also move the notes on the second and third strings to come up with a few other useable triadic chords.
Here are a few options that don’t change the key.
The Minor Barre Chord Triadic Shape
To make this chord minor is quite easy. Simply move the note at the fifth fret on the second string down one semitone to the fourth fret.
The D Minor Triadic Chord Shape
In a similar manner, we can use the D chord shape, where the ghost note is a root D to find another useful triadic chord.
All together, this gives you 17 different movable shapes that you can work with. Not only that, but they’re really simple and useful. You’ll use these small chords in varying forms, regardless of how good or technical you get on the guitar.
Often it’s the simple shapes and patterns that end up being the most useful.
Practice these, memorize them and make them a part of your chord vocabulary.
Building from Guitar Intervals
So you’ve seen how you can take guitar intervals and use them to build out your knowledge of chords and improve your ability to navigate the fretboard.
My advice to you is to get good at understanding and applying this concept before you set out to memorize more chords and scales.
Odds are that you won’t find the chord and scale memorization process nearly as challenging if you understanding intervals and basic chord construction.
It’s an incremental learning method.
Start with the most basic elements and build out your knowledge from there.
Know What to Memorize
Becoming a good musician means you’re going to spend some time memorizing, either intentionally or simply because of repeated exposure.
But it benefits a music student greatly if they know what to memorize, as opposed to trying to retain every chord, scale and element of theory they might see.
That can be extremely frustrating and taxing on one’s motivation.
What guitar players need to memorize is often more succinct and nuanced.
Intervals, dyads and triads are great examples of this. Because instead of learning tons of different chords, we learn a simple process that shows us how they’re created. That’s where your memory effort should show up, and not necessarily to digest tons of diagrams from a chord library.
Am I saying don’t memorize chords?
No, of course not.
But I am saying that you should be smart about how you memorize them and that you should take the time to understand the processes and smaller building blocks behind the shapes.
It’s a great instructional on fretboard notes and intervals with tons of exercises and good, succinct information.
Interval Studies and Lead Guitar Technique by Barrett Tagliarino is also a good follow up.
Additionally, you can refer to the three articles from which this material was primarily derived from:
- Intervals Explained
- The Complete Guide to Actually Understanding Seventh Chords
- Simple Guitar Chords Using Dyads and Triads
If you want to stay up-to-date on content like this, you can jump onto our mailing list and subscribe for updates that occur sparingly.
Other Beginner Lead Guitar Resources
55 Guitar Exercises for Improving Accuracy: A massive collection of fretboard exercises designed to strengthen hands and improve dexterity.
Complete Guitar Intervals Lesson: A shorter and more succinct lesson on guitar intervals, complete with tabs and charts.
E String Notes Fretboard Memorization: Quick and easy guide to memorizing the fretboard notes on both the high and low E strings.
Guitar Scales Explained in Simple Illustrations: An explanation of the theory and practical application of guitar scales.
Flickr Commons Image Courtesy of Kmeron