Made of material, without damage to your guitar strings. Can adjust the strap to fine-tune your dampener pressure at Weakening sound of guitar Easy to use, no tools or special Help overtones and resonances, reduce unnecessary string noise of string instruments, which creates an excellent playing environment for your recording or live performance. And you can practice the guitar better while not disturbing other people. It contains S and L size, small strap can be used with 6-string electric/wood guitar, classical guitar, four-string bass. Large strap is suitable for 7~10-string electric guitar, 5~10 -string electric bass. Suitable for guitars, basses and other stringed instruments. A great assistant tool for guitar/ bass players. material, no any damage to your guitar strings.Easy to use, no tools or special installation required. Material: cotton colour: black Package Contents: 2 x Guitar Fret Strings Mute(17cm, 19cm) 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.