AS15 One Way Clutch One Clutch AS15 = NSS15 AS15 is a one-way clutch,that is used for Overrunning, Indexing and Backstopping, this type is non-bearing supported, this is exactly the same size as any 6202 ball bearing, you will need one of the 6202 beairngs to support it, one way Sprag/Clutch Freewheel and also called as Backstops. AS15 is 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.