Cobra 3 RPT Slip-On Mufflers For Harley Softail Cobra consistently offers the market some of the top performing products at an extremely affordable price. Take these 3 RPT Slip-On Mufflers for example, as it uses constant velocity cores and bonded e-glass and stainless steel mesh to unbeatable performance as well as sound. Features: The RPT designation comes from adapting the design from out Race-Pro 4 muffler into this 3 size The bodies begin as 3 in. at the front until they expand to 3-1/2 at the rear The black tip is also the Race-Pro machined design that's held in place with 12-point bolts Billet RPT tip finishes off the rear 2 spun-louvered baffle creates back pressure and accelerates exhaust gases