Sprocket Bore Diameter 1 in For Chain Pitch 1 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 1 7/8 in Number of Teeth 12 Outside Diameter 4.33 in Pitch Diameter 3.864 in Bore Type Plain Chain Number 80 Finish Black Oxide For Pitch Type Single Pitch Hub Diameter 3 1/8 in Hub Projection 1.05 in Includes Set Screws Keyway Yes Keyway Depth 1/8 in Keyway Width 1/4 in Length through Bore 1 9/16 in Material Grade 1045