Vise Grip Lady P/S Finger Insert – 10 Pack of GripsOne side of the insert is a Semi cut and the other side is a Power LiftDrill bit size required: 7/810 Pack is one size and one color. No mixing.The Power Lift helps the bowler create more revs with the 1/4″ forward pitch that aids grip. The semi side provides a bump for additional grip when inserting your finger past the first joint.Lady Vise P/S Inserts are available in 8 sizes and 9 colors.Sizes 17/32 through 3/4 have O.D. of 7/8″