Improve your swing and gain power with the ProHitter(R) Batting Aid. Trusted and used by the Pros, this batting aid creates the correct grip technique to increase bat speed, power, and control. The ProHitter(R) Grip Aid also prevents bone bruises and stinging when you are jammed with an inside pitch. Fits both right and left handed baseball or softball players and can be used with or without a batting glove. Area for thumb may stretch. FEATURES: Made of durable rubber-like resin Helps increase bat speed, power and control Prevents bone bruises Fits both right and left handed baseball or softball players Can be used with or without a batting glove Area for thumb may stretch Made in the USA Model: 133Y ProHitter PROHITTER(R) SIZE CHART Adult: 7/8" thumb hole diameter Midsize: 6/8" thumb hole diameter Youth: 4/8" thumb hole diameter