Roller Chain Sprocket Bore Diameter 5/8 in For Chain Pitch 1/4 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 5/8 in Number of Teeth 18 Outside Diameter 1.568 in Pitch Diameter 1.44 in Bore Type Fixed Chain Number 25 Finish Black Oxide Hub Diameter 1 1/8 in Hub Projection 0.39 in Includes Set Screws Keyway Yes Keyway Width 3/16 in Length through Bore 1/2 in Number of Set Screws 2