Sprocket Bore Diameter 3/8 in For Chain Pitch 1/4 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 1 3/8 in Number of Teeth 40 Outside Diameter 3.327 in Pitch Diameter 3.187 in Bore Type Plain Chain Number 25 Finish Black Oxide For Pitch Type Single Pitch Hub Diameter 2 in Hub Projection 0.64 in Includes Set Screws Keyway Yes Keyway Depth 1/16 in Keyway Width 1/8 in Length through Bore 3/4 in Material Grade 1045