Roller Chain Sprocket Bore Diameter 1 3/16 in For Chain Pitch 5/8 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 1 3/16 in Number of Teeth 20 Outside Diameter 4.32 in Pitch Diameter 3.995 in Bore Type Fixed Chain Number 50 Finish Black Oxide Hub Diameter 3 in Hub Projection 0.657 in Includes Set Screws Keyway Yes Keyway Width 1/4 in Length through Bore 1 in Number of Set Screws 2