AS17 One-Way 17x40x12 Bearing Support Required Backstop ClutchAS17 One Way Clutch One Clutch AS17 = NSS17 AS17 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 6203 ball bearing, you will need one of the 6203 beairngs to support it, One way Bearing Sprag Clutch Freewheel and also called as Backstops. AS17 is used in any application that requires one direction rotation, such as mining, hydraulic, textile, printing