JoPo Grips is a company with a new interchangeable thumb insert called the Twist. This insert uses patented technology, creating a durable bowling grip that will enhance your bowling experience. The thread-like feature absorbs the load of the weight and the velocity of the bowling ball delivery. The Twist cannot be removed from the bowling ball without the inner being rotated 360º.For easy insertion or removal of the Jopo Twist Interchangeable thumb if needed or desired.Downloads:- Pro Shop Installation Instructions- Important Information for Pro Shops And Bowlers- Bowler InstructionsVideos available on product page