A great, No-Slip Endpin Ball with threaded insert (EP-BALL plus EP-INS-THR). Developed and tested by a former member of the Philadelphia Orchestra, this high-grip endpin ball fits all threaded endpin tips which use a standard M10 thread (Saddle Rider Music, Upton Bass, New Harmony Music, and more.) The size and grip of the rubber allow bassists and cellists the same security offered by a high-quality rockstop, but without being anchored to one spot on the floor. This is a great way to protect hardwood floors from endpin damage! If the ball becomes dirty and starts to loose its grip, just wipe it off with your hand or a rag to regain its excellent grip. The proprietary rubber mix was carefully engineered specifically for Saddle Rider Music M10threaded bass and cello endpin tips.