Steeda's GT500 supercharger pulley directly replaces the factory supercharger pulley and gives approximately 3 PSI of extra boost. Manufactured out of billet steel, not aluminum like others on the market and nickel-plated for durability and great looks.In house testing has shown increases of over 125 HP and 100ftlbs of Torque to the rear tires!!! (Tested on GT500 with Steeda CAI, Pulley and Tune) Product Benefits More Horsepower and Torque to the rear tires!! 100% made in the USA by Steeda. Exceeds OEM Quality, with superior durability.