Features: The 18cm one is suitable for 6-string acoustic/electric/classic guitars. The 19cm one is suitable for 7-string acoustic/electric/classic guitars, bass or other string instrument fingerboard width above 45mm. A great assistant tool for guitar/ bass players for reducing the noise caused by unnecessary vibration of the strings. Provides and keep clean lines without unwanted string noise while practice, learning and performance. Made of high quality soft and fine material, high strength and good tenacity, durable to use and no any damage to your guitar strings. Easy to use, no tools or special installation required, quick to wrap, suitable for daily use. Specifications: Length: 18cm / 19cm (Optional) Material: Cotton Package Weight: 11g / 0.39oz Package Size: 15 * 11 * 2cm / 5.91 * 4.33 * 0.79in Package List: 1 * String Mute