Roller Chain Sprocket; 45MM Bore; 40-2 Chain; 25 Teeth; 2 Row of Teeth; No Hardened Teeth; 108.153MM Outside Diameter; 101.33MM Pitch Diameter; B-Hub One Side; Finished Bore Mount; No Bushing; 12.7MM Chain Pitch; ANSI Roller Chain; No Keyway; Steel Material