Single speed bicycle freewheel, model SC-FR-103, offered in 16T, 18T, 20T, 22T and 24T sizes. A freewheel threads onto the rear hub, drives the rear wheel while the rider pedals and lets the bicycle coast when pedalling stops. This one is a single toothed sprocket around a round threaded body, in a dark grey finish. It comes with half or full balls, and the tapping is 1/2" x 1/8" x 24 TPI/1 mm. Finish is Black, BLP or Golden, to order.