Roller Chain Sprocket, Bore Diameter 1 1/2 in, For Chain Pitch 1/2 in, For Number of Strands Single, Hub Type One Side, Material Steel, Maximum Bore Diameter 1 1/2 in, Number of Teeth 40, Outside Diameter 6.65 in, Pitch Diameter 6.373 in, Bore Type Fixed, Chain Number 40, Finish Black Oxide, Hub Diameter 3 1/2 in, Hub Projection 0.841 in, Includes Set Screws, Keyway Yes, Keyway Width 3/8 in, Length through Bore 1 1/8 in, Number of Set Screws 2