Roller Chain Sprocket; 1-3/8" Bore; 50 Chain; 17 Teeth; 1 Row of Teeth; No Hardened Teeth; 3.718" Outside Diameter; 3.401" Pitch Diameter; B-Hub One Side; Finished Bore Mount; No Bushing; 5/8" Chain Pitch; ANSI Roller Chain; Keyway; Steel Material