Roller Chain Sprocket Bore Diameter 20 mm For Chain Pitch 1/2 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 53 mm Number of Teeth 28 Outside Diameter 4.79 in Pitch Diameter 113.43 mm Bore Type Plain Chain Number 08B Finish Black Oxide Hub Diameter 82 mm Hub Projection 0.891 in Keyway No Keyway Depth Not Applicable Keyway Width Not Applicable Length through Bore 30 mm Number of Set Screws 0 Set Screw Location Not Applicable