High-temperature stainless steel cones have fully radiused edges that smooths out the power curve for improved engine response, especially low-end torque. Generates correct levels of backpressure for increased horsepower. Fit most stock and aftermarket exhaust systems; fit 1-3/4"-2" i.d. exhaust pipes. New Vortex design increases back pressure, improving torque and horsepower. Made in the U.S.A..