Roller Chain Sprocket Bore Diameter 25 mm For Chain Pitch 1/2 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 25 mm Number of Teeth 14 Outside Diameter 2.58 in Pitch Diameter 57.07 mm Bore Type Fixed Chain Number 08B Finish Black Oxide Hub Diameter 42 mm Hub Projection 0.812 in Includes Set Screws Keyway Yes Keyway Width 8 mm Length through Bore 28 mm Number of Set Screws 2