Roller Chain Sprocket Bore Diameter 1/2 in For Chain Pitch 3/8 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 1 3/8 in Number of Teeth 21 Outside Diameter 2.71 in Pitch Diameter 2.516 in Bore Type Plain Chain Number 35 Finish Black Oxide Hub Diameter 2 in Hub Projection 0.707 in Keyway No Keyway Depth Not Applicable Keyway Width Not Applicable Length through Bore 7/8 in Number of Set Screws 0 Set Screw Location Not Applicable