Roller Chain Sprocket; 1/2" Bore; 25 Chain; 25 Teeth; 1 Row of Teeth; No Hardened Teeth; 2.129" Outside Diameter; 1.995" Pitch Diameter; B-Hub One Side; Finished Bore Mount; No Bushing; 1/4" Chain Pitch; ANSI Roller Chain; Keyway; Steel Material