Sprocket Bore Diameter 3/4 in For Chain Pitch 1/2 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 3/4 in Number of Teeth 40 Outside Diameter 6.65 in Pitch Diameter 6.373 in Bore Type Fixed Chain Number 40 Finish Black Oxide Hub Diameter 3 1/2 in Hub Projection 0.841 in Includes Set Screws Keyway Yes Keyway Depth 3/32 in Keyway Width 3/16 in Length through Bore 1 1/8 in Number of Set Screws 2