These mufflers have been dyno tested and show a 12% increase in torque and 7% increase in power Produce the Khrome Werks signature, authoritative tone without annoying high-frequency noises Absorptive baffle covered with stainless steel mat and high temp fiberglass developed just for the Milwaukee-Eight 16-gauge muffler bodies Made in the U.S.A. MUFFLER 4.5"TRACER M8 SM