Roller Chain Sprocket Bore Diameter 1 in For Chain Pitch 5/8 in For Number of Strands Double Hub Type One Side Material Steel Maximum Bore Diameter 1 in Number of Teeth 25 Outside Diameter 5.32 in Pitch Diameter 4.987 in Bore Type Fixed Chain Number 50-2 Finish Black Oxide Hub Diameter 3 in Hub Projection 0.83 in Includes Set Screws Keyway Yes Keyway Width 1/4 in Length through Bore 1 7/8 in