4-1/2" 16-gauge muffler body, These mufflers have been dyno-tested and show a 12% increase in torque and 7% increase in power, Engineered for performance, style, and sound, Absorptive baffle wrapped with stainless steel mat and high-temp fiberglass, Produce the Khrome Werks signature authoritative tone without annoying high-frequency noises, Improved torque and horsepower from the hit of the throttle, Billet aluminum tips can be rotated 360? at 90? increments, Bolt-in optional inserts available that comply with SAE J2825 sound test with no appreciable loss of performance, Optional performance inserts boost low-end performance and enhance sound, Sold in pairs, Made in the U.S.A.