Features: Upgraded one-key guitar chord practice tool specially designed for 36-41 inch folk guitars, and 43-45mm wide of first fret is proper. Supports 9 universal chords and 15 extended chords, which is suitable for almost all of popular songs. Simple to use, just press the button with chord name, then you can play the chords of the songs easily. An ideal assistant tool for folk guitar, and allows beginners to learn guitar chords quickly and play the guitar without pain. Not suitable for left-handed, 12-string, half-sized(Children's) classical and electric guitars. Please measure your guitar neck before ordering. Specifications: Color: Black Universal Chords: D, BM, F, C, G, AM, EM, DM, AM7 Extension Chords: cmaj7, csus4, Asus2, Bsus2, E, D, C, CM, AM, CM, Dsus4, Esus4, Am/c, F6, G