BORLA's XR-1® Raceline products are the choice of today's hottest drag and oval track racers. Featuring a patented uninterrupted-flow design and multi-core technology, BORLA's XR-1® mufflers actually outflow a straight piece of pipe in repeated testing. XR-1® race products are made in the USA and constructed of high-quality austenitic stainless steel for track tough durability. They meet the strictest noise requirements and use sound-absorbing stainless steel packing to protect against burnout. Hands down, BORLA's XR-1® Raceline offers the best balance of sound and power.