80BS11H X 1 3/8-A Sprocket, Bore Diameter 1 3/8 in, For Chain Pitch 1 in, For Number of Strands Single, Hub Type One Side, Material Steel, Maximum Bore Diameter 1 3/8 in, Number of Teeth 11, Outside Diameter 4.01 in, Pitch Diameter 3.55 in, Bore Type Fixed, Chain Number 80, Finish Black Oxide, Hub Diameter 2 13/16 in, Hub Projection 1.05 in, Includes Set Screws, Keyway Yes, Keyway Depth 5/32 in, Keyway Width 5/16 in, Length through Bore 1 5/8 in, Number of Set Screws 2