AMA Verlag Der AMA-Quintenzirkel

This is a brilliant and simple product: a really handy cycle of fifths, with the added advantage of providing extra key sense. The inner wheel enables the user to dial in a 6-chord trick for each key, with the dominant chord of the relative minor shown in another window.
There are several such products: my students all prefer using this one. It is neat and efficient. Useful for analysis, ear training and for creativity: songwriting, composing etc.

Simple card wheel that will give you the chords for each key. Also indicates the scale degree, name (dominant etc..), basic open chord fingering for each chord, and shows the sharps and flats for each scale/key.
Very useful quick reference if, like me, you find this stuff difficult to memorise!
Not made of the toughest card, but pretty good for the price.

I recommend to everyone