... sports crazy ball Wrist ball with NEON&counter Increase strength of fingers,wrists,hands,forearms, ... over 12,000 RPM.TheoryLike gyroscopes.centrifugal force and inertia are applied.Function:1.Perfect exercise gadget ... wrists, hands, forearms, biceps, triceps, ligament and shoulders3. Great benefit and avoid the ligament injuries who are the typists ... exercise wrist exercise ball with light and counter