Polytree Hand Grip Strengthener Exercise Finger Silicon Ring Trainer PERFECT SIZE HAND STRENGTHENERS. Size S: 7cm x 3.5cm x 1.8cm, Size L: 8.8cm x 4.5cm x 2.2cm. Sized especially for female with average hand, elder, and youngsters. GREAT FOR YOUTHS & GAMERS - flex and strengthen muscles of the hand, stop cramping up caused by too much computer work. GOOD MATERIAL--The grippers are made from premium silicone, the high quality item can strenghten your muscle. 3 RESISTANCE LEVELS FOR YOUR CHOICE- 30lb, 40lb and 50lb round hand grips for training in all three major grip areas, namely crushing, pinching and even extension. Package Includes: 1 x Silicon Hand Grip Strengthener Ring.