Shock absorbing device made of silicone developed and patented by Babolat. Clips on easily between the strings for contact and pressure over all the diameter of the string. Vibration absorption enhanced thanks to the anticinetic system of small, encased ball bearings.1 per packAvailable Colors: Clear OR BlackMidwest Sports only ships Babolat products to domestic addresses in the U.S. and U.S. Territories.