Roller Chain Sprocket; 1-1/2" Bore; 12B-2 Chain; 20 Teeth; 2 Row of Teeth; Hardened Teeth; 5.186" Outside Diameter; 4.794" Pitch Diameter; B-Hub One Side; Finished Bore Mount; No Bushing; 3/4" Chain Pitch; ISO Roller Chain; Keyway; Steel Material