Sprocket Bore Diameter 1 3/4 in For Chain Pitch 1 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 1 3/4 in Number of Teeth 12 Outside Diameter 4.33 in Pitch Diameter 3.864 in Bore Type Fixed Chain Number 80 Finish Black Oxide Hub Diameter 3 1/8 in Hub Projection 1.05 in Includes Set Screws Keyway Yes Keyway Depth 3/16 in Keyway Width 3/8 in Length through Bore 1 5/8 in Number of Set Screws 2