Roller bearing(backstop) CKA is a type sprag freewheel supported by double bearings.Used for speed 600-1500r/min,torque 180--800 Roller bearing(backstop ... ,one way clutch,one way bearing) WKA is a basic sprag type freewheel. Bearings ... machine, medical machine, bucket, spinning and conveyor, weaving machine etc.. roller bearing CKA