The 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 bonded e-glass and stainless steel mesh. The RPT designation comes from adapting the design of Cobra’s Race-Pro 4″ muffler into this 3″ size. The bodies begin as 3″ at the front until they expand to 3-1/2″ at the rear. Tip is the Race-Pro machined design that’s held in place with 12-point bolts.