Roller Chain Sprocket Bore Diameter 1 1/4 in For Chain Pitch 5/8 in For Number of Strands Double Hub Type One Side Material Steel Maximum Bore Diameter 1 1/4 in Number of Teeth 13 Outside Diameter 2.91 in Pitch Diameter 2.612 in Bore Type Fixed Chain Number 50-2 Finish Black Oxide Hub Diameter 1 7/8 in Hub Projection 0.705 in Includes Set Screws Keyway Yes Keyway Width 1/4 in Length through Bore 1 3/4 in