Roller Chain Sprocket Bore Diameter 12 mm For Chain Pitch 3/8 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 12 mm Number of Teeth 16 Outside Diameter 2.2 in Pitch Diameter 48.82 mm Bore Type Fixed Chain Number 06B Finish Black Oxide Hub Diameter 37 mm Hub Projection 0.775 in Includes Set Screws Keyway Yes Keyway Width 4 mm Length through Bore 25 mm Number of Set Screws 2