Cobra Slip-On For Harley Flsb 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 Harley-Davidson Softail motorcycle. There are also no visible outer screws, providing a sleek, stylish look. Features: 4 round muffler Rolled scalloped tip that matches an inner core mirrored with the same scalloped shape Inner tip is part of the constant velocity, tuned core that gives the muffler its great sound and performance Spiral louvered cores deliver specific acoustic tuning producing a distinctive rumble under acceleration and a gruff growl on run down No unsightly external screws holding in the tip or core gives a smooth undisturbed finish Note: Installation may require a new muffler gasket OEM 65900040, which is not included.