Made from high quality muting materials, soft and durable without scratching the fretboard or strings. String dampener avoids unwanted noise and overtones caused by vibrations while you are practicing and performing. Easy to install and uninstall and fastens securely on . When not in silent used can also be used 6 a picks holder. Metal size is 8 x1.2 x 1.2cm, plastic mute size is 8 x1.8 x 1cm,Easy to use, and does not require tools or installation. Universal and adjustable, it is really a tool for the guitar beginner. color:Black+silver Material:metal+EVA Package Contents: 2 x Guitar Fret Strings Mute 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.