Sprocket Bore Diameter 1 1/2 in For Chain Pitch 3/4 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 1 1/2 in Number of Teeth 13 Outside Diameter 3.49 in Pitch Diameter 3.134 in Bore Type Fixed Chain Number 60 Finish Black Oxide Hub Diameter 2 3/8 in Hub Projection 0.791 in Includes Set Screws Keyway Yes Keyway Depth 3/16 in Keyway Width 3/8 in Length through Bore 1 1/4 in Number of Set Screws 2