The Tiny-Clutch 1478 Indexing Sprocket Clutch is based off of our SP75D Wrap Spring Clutch. This clutch features a 48 tooth, 25 pitch Sprocket, a 1 lug (Single Revolution) collar & an over-tavel stop. It has a 3/8" | 9.5mm bore, mounts with a cross hole, & replaces R. Funk Part # A8523.