If you’re looking to get the most sound out of your new Softail, these are for you.. Mufflers make use of all of the high-tech features of Cobra’s regular three-inch slip-on mufflers, including two-inch constant velocity cores for exceptional sound and performance, as well as the bonded e-glass and stainless steel mesh. The constant velocity cores are designed specifically for the Milwaukee Eight engine platform, to provide the best sound and performance. The 3-inch muffler body morphs to 3.25-inches at the rear, and the RPT tip finishes off the rear.