Detail 01
Rotating wheel design
You line up one key and read the chords that belong to it, instead of calculating intervals each time.

Independent shopping perspective
A rotating plastic disc that shows which chords belong to each key. A theory shortcut for songwriters and players working out progressions.

Strong match
Consider the trade-offs
What matters in use
Catalog numbers tell only part of the story. These are the details most likely to change how this product feels, sounds, or fits into a setup.
Detail 01
You line up one key and read the chords that belong to it, instead of calculating intervals each time.
Detail 02
Survives being tossed in a gig bag. It will not tear or dog-ear the way a card or paper chart does.
Detail 03
Bigger than a phone but flat. It sits on a music stand or desk rather than in a pocket.
Detail 04
Slim enough to slide into a folder or the sleeve of a gig bag alongside sheet music.
Detail 05
Light enough that it will slide on a stand — angle the stand or weight it down.
Final check
Product questions
Straight answers to the questions shoppers most often ask about this product.
You set it to a key and it shows which chords are diatonic to that key, plus the related minor. It replaces the mental math of the circle of fifths.
Neither specifically. It deals in keys and chord names, so it works the same for any instrument.
No. Reading chords off it requires no theory, though it helps you learn key relationships over time.
At 12 by 9 inches and very thin, it slides into a sheet music pocket or folder, not a small accessory pouch.
Reference
The complete catalog record, organized around the decisions musicians make when comparing gear.