Roller Chain Sprocket Bore Diameter 30 mm For Chain Pitch 3/4 in For Number of Strands Single Hub Type One Side Material Steel Maximum Bore Diameter 30 mm Number of Teeth 19 Outside Diameter 5 in Pitch Diameter 115.74 mm Bore Type Fixed Chain Number 12B Finish Black Oxide Hub Diameter 90 mm Hub Projection 0.94 in Includes Set Screws Keyway Yes Keyway Width 8 mm Length through Bore 35 mm Number of Set Screws 2