Roller Chain Sprocket Bore Diameter 1/4 in For Chain Pitch 1/4 in For Number of Strands Single Hub Type No Hub Material Steel Maximum Bore Diameter 7/8 in Number of Teeth 20 Outside Diameter 1.729 in Pitch Diameter 1.598 in Bore Type Plain Chain Number 25 Finish Black Oxide Hub Diameter Not Applicable Hub Projection Not Applicable Keyway No Keyway Depth Not Applicable Keyway Width Not Applicable Length through Bore 1/8 in Number of Set Screws 0