CSK15 AMBER One-Way Clutch Bearing - Sprag Freewheel BackstopCSK15 AMBER One way (clutch) Bearing The CSK series is a one way (clutch) ball bearing, One way Bearing Sprag Clutch Freewheel and also called as Backstops, The one way bearings are used in any application 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 shortage. CSK15 AMBER Bearing