The tone completer has the guitar world buzzing Simulates the effects of actual playing to bring out the best in your guitar. This revolutionary "play-in" simulator is based on the observation that the more an acoustic instrument is played, the faster it reaches its full sound potential (its "play-in" period). The tone completer applies direct vibration to a guitar at controlled frequencies, to the effects of actual playing. Many players report increased volume and dynamic range in their instruments after using the device between playing sessions. Built-in battery: 800 mA Application: Guitar/Ukulele Colour: black Material: ABS Size: 7.5 x 5.5 x 5cm Package Contents: 1 x Sound Opener 1 x connection line Note: Do not use while charging Only the above package content, other products are not included. Note: Light 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.