... It resembles a roller bearing, but instead of cylindrical rollers, non-revolving asymmetric figure-of-eight shaped sprags are used. When the ... rollers tilt slightly, producing a wedging action and binding because of friction. The sprags are spring-loaded so that they ... Primary drive, Conveyors, Overrunning, Indexing, Backstopping, Hoist load brake. High quality freewheel sprocket of sprag freewheel