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 that have rubber 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 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 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 down with the same finger. Material: ABS colour: black Package Contents: 1 x Guitar aid 1 x Guitar chord diagram Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.