... unit rotates in one direction the rollers slip or free-wheel, but when a torque is applied in the opposite direction ... friction. The sprags are spring-loaded so that they lock with very little backlash.Applications: Automatic transmissions, Helicopters, Motorcycle, Starters, Primary ... , Conveyors, Overrunning, Indexing, Backstopping, Hoist load brake. Sprag Clutch Bearings with best quality