The GripMaster® ProTM Hand Exerciser is a simple way to increase hand strength for improved shooting control, accuracy and weapon retention. The GripMaster® sets itself apart from similar products because it isolates each finger. That's why it's used by the FBI, ATF and DEA. Of course, that added strength will also help you in countless other parts of your life, too... from your golf swing to playing guitar or spending long hours at the computer or gaming console. This ProTM model features extra-heavy tension for a serious workout.