Roller Chain Sprocket Bore Diameter 1 in For Chain Pitch 3/4 in For Number of Strands Double Hub Type One Side Material Steel Maximum Bore Diameter 1 in Number of Teeth 21 Outside Diameter 5.43 in Pitch Diameter 5.033 in Bore Type Fixed Chain Number 60-2 Finish Black Oxide Hub Diameter 4 1/8 in Hub Projection 0.784 in Includes Set Screws Keyway Yes Keyway Width 1/4 in Length through Bore 2 1/8 in