Single Strand Sprocket Bore Diameter 1 in For Chain Pitch 5/8 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 1 in Number of Teeth 21 Outside Diameter 4.52 in Pitch Diameter 4.194 in Bore Type Fixed Chain Number 50 Finish Black Oxide For Pitch Type Single Pitch Hub Diameter 3 in Hub Projection 0.657 in Includes Set Screws Keyway Yes Keyway Depth 1/8 in Keyway Width 1/4 in Length through Bore 1 in Material Grade 1045