Roller Chain Sprocket Bore Diameter 19 mm For Chain Pitch 3/8 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 19 mm Number of Teeth 20 Outside Diameter 2.65 in Pitch Diameter 60.89 mm Bore Type Fixed Chain Number 06B Finish Black Oxide Hub Diameter 49 mm Hub Projection 0.893 in Includes Set Screws Keyway Yes Keyway Width 6 mm Length through Bore 28 mm Number of Set Screws 2