One-Key Guitar Chord Trainer with 18 Buttons Folk Guitar Chords Learning System Practice Assist Tool Finger Teaching Aid for Adults Children BeginnersFeature: The is for those who have given up the guitar due to finger pain, string buzzing, or the need to develop finger callouses when fretting the strings directly. You should make every effort to play without it. The is attached securely on the neck of your guitar over the first three frets. It rests on three legs that have rubber caps on the ends to protect your guitar. The two legs at the front of the will stand between strings 1 and 2 and strings 5 and 6. It is important that the legs do not interfere with these vibrating strings. Therefore, you must make two measurements on your guitar to make sure that the will fit properly: First, the vibrating string length should be 24 inches to 26 inches. Second, the distance between strings 1 and 6 directly above the third should be one and a half inches to one and five eights inches. When the is properly installed, and no buttons are pushed down, there will be no interference with the vibrating strings. . You will produce perfect and clear tones that are very difficult to achieve when fretting the strings without the. With the 18 buttons, over 110 chords are available. These include all the basic chords for the guitar keys of C, D, E, G and A. You also have the full scales of C and F In the chord diagrams, which are included. Sometimes two or more buttons are simultaneously pushed dow