Roller Chain Sprocket Bore Diameter 12 mm For Chain Pitch 1/2 in For Number of Strands Single Hub Type No Hub Material Steel Maximum Bore Diameter 51 mm Number of Teeth 23 Outside Diameter 4 in Pitch Diameter 93.27 mm Bore Type Plain Chain Number 08B Finish Black Oxide Hub Diameter Not Applicable Hub Projection Not Applicable Keyway No Keyway Depth Not Applicable Keyway Width Not Applicable Length through Bore 3/16 in Number of Set Screws 0 Set Screw Location Not Applicable