PCGT Timing Belt Pulley For Belt Series Poly Chain GT Carbon For Belt Width 21 mm For Bushing Size 1610 For Bushing Type Taper Lock For Use With Poly Chain GT Carbon Belts Material Steel Maximum Bore Diameter 1 5/8 in Minimum Bore Diameter 1/2 in Number of Teeth 39 Outside Diameter 4.331 in Pitch 8 mm Pitch Diameter 3.91 in Face Width 1.203 in Features Built for High-Torque Low-Speed Applications Outperforms Industry Standards Superb Flexibility Finish Black Oxide