3" RPT Mufflers for '07-'13 XL - ChromeThe RPT slip ons make use of all of the high tech features of Cobra's regular 3" slip on mufflers, including 2" constant velocity cores for exceptional sound and performance, as well as the bonded e glass and stainless steel mesh. The RPT designation comes from adapting the design from Cobra's Race Pro 4" muffler into this three inch size. The bodies begin as 3" at the front until they expand to 3. 5" inches at the rear. The tip uses the Race Pro