Cobra 4" RacePro Slip On Mufflers Chrome 6218 4in. round muffler front expands just at the rear to reach a 4.5in. diameter, capped off by a thin line black tip that is held in place with 7 stainless steel aircraft-style, 12-point bolts Black finish on the tip is matched with the black finish on the laser-cut steel strap that tightly encircles the muffler Race Pro mounts the same way as nearly every slip-on muffler from Cobra. The strap clamps tightly around the muffler and bolts to the bikes hanger mounts located beneath the saddlebags PEM fasteners in the wrap make mounting a simple task of threading in a bolt from the upper bracket into the Cobra strap