Roller Chain Sprocket Bore Diameter 1 5/8 in For Chain Pitch 5/8 in For Number of Strands Double Hub Type One Side Material Steel Maximum Bore Diameter 1 5/8 in Number of Teeth 18 Outside Diameter 3.92 in Pitch Diameter 3.599 in Bore Type Fixed Chain Number 50-2 Finish Black Oxide Hub Diameter 2 7/8 in Hub Projection 0.705 in Includes Set Screws Keyway Yes Keyway Width 3/8 in Length through Bore 1 3/4 in