Sprocket Bore Diameter 1 1/4 in For Chain Pitch 3/4 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 1 1/4 in Number of Teeth 40 Outside Diameter 9.98 in Pitch Diameter 9.56 in Bore Type Fixed Chain Number 60 Finish Black Oxide Hub Diameter 4 1/4 in Hub Projection 0.791 in Includes Set Screws Keyway Yes Keyway Depth 1/8 in Keyway Width 1/4 in Length through Bore 1 1/4 in Number of Set Screws 2