GFRN12 12mm Bore one Way Clutch with Keyway 12x62x42mmGFRN12 12mm Bore Clutch with a Keyway 12mm x 37mm x 20mm GFRN12 is a one way clutch. GFRN has a keyway on the outside diameter to transmit the torque. One way Clutch Freewheel and also called as Backstops. It is used in any applications that requires one direction rotation, such as mining, hydraulic, textile, printing and washing machines, conveyor systems that carry products to a higher level should not be reversed because of gravity during any power