Maximize the Proper Grip Technique with the Patented Batting Aid Used by the Top Pros. ProHitter is a durable, rubber-like resin which, when worn correctly on the thumb of the top hand holding the bat, creates the correct grip technique to increase bat speed, power, and control. It also prevents a batter from getting stung or bone bruises when a batter gets jammed with an inside pitch. A large percentage of baseball's best pro players are using Prohitter to help increase their hitting performance. For baseball and softball, with or without a batting glove, with wood or aluminum bats. Fits both right and left handed players. ProHitter product holds five U.S. patents.