Roller Chain Sprocket; 3/4" Bore; 40 Chain; 23 Teeth; 1 Row of Teeth; Hardened Teeth; 3-15/16" Outside Diameter; 3-43/64" Pitch Diameter; C-Hub Both Sides; Finished Bore Mount; No Bushing; 1/2" Chain Pitch; ANSI Roller Chain; Keyway; Steel Material