Gearbelt Pulley Bore Diameter 1/2 in For Belt Series SilentSync For Belt Width 25 mm For Use With 25 mm Belt Material Aluminum Maximum Bore Diameter 1 1/16 in Number of Teeth 20 Outside Diameter 1.969 in Pitch 8 mm Pitch Diameter 2.005 in Bore Type Plain Face Width 26 mm For Belt Trade Size SilentSync Hub Diameter 1 5/8 in Hub Projection 15/32 in Hub Type One Side Keyway No Keyway Depth Not Applicable Keyway Width Not Applicable Length through Bore 1 1/2 in