Cobra El Diablo Slip-On Mufflers For Harley Touring The El Diablo slip-on mufflers are a new design all inspired from Cobras El Diablo 2-into-1 which was released 2017. The slip-ons begin off as a 2 body which then expands to 4 at the end. As far as the internals go, as expected the louvered core provides the roar and horsepower gains you expect from Cobra. Features Utilizes a cone style muffler body Expands to 4 at the rear Mechanical baffling system offers an increase in sound and power Billet aluminum reverse cone tip finishes off the rear Tip is powder-coated black, with Cobra etched on top