TRAP Timing Belt Pulley Bore Diameter 3/4 in For Belt Series H For Belt Width 3 in For Use With 3 in Wide Belts Material Ductile Iron Maximum Bore Diameter Not Applicable Number of Teeth 20 Outside Diameter 3.42 in Pitch 0.5 in Pitch Diameter 3.183 in Bore Type Plain Face Width 3.375 in Features Built for High-Torque Low-Speed Applications Outperforms Industry Standards Superb Flexibility Finish Black Oxide For Belt Trade Size H Hub Diameter 2 1/2 in Hub Projection 13/16 in