Cobra USA COB-6108RB 4" 909 Back Slash Slip-On Mufflers Black for Touring 17-UpDescription for Cobra 909 Twins Black Slip On Mufflers Want that classic Harley rumble without dropping months' worth of bike payments? The Cobra 4" 909 Twins Slip On Mufflers feature a scalloped and smooth rolled outer tip matched by a scalloped inner tip. That inner tip is part of the constant velocity, spiral louvered cores that give these mufflers their great performance and the deep, throaty, instantly recognizable sound you expect from your