Sprocket Bore Diameter 3/4 in For Chain Pitch 5/8 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 2 in Number of Teeth 21 Outside Diameter 4.52 in Pitch Diameter 4.194 in Bore Type Plain Chain Number 50 Finish Black Oxide Hub Diameter 3 in Hub Projection 0.657 in Keyway No Keyway Depth Not Applicable Keyway Width Not Applicable Length through Bore 1 in Number of Set Screws 0 Set Screw Location Not Applicable