Kerker Stouts are chrome plated or black coated 4" (10 cm) diameter slip-on mufflers, designed to fit the stock head pipes. These slip-ons feature a traditional core, which targets a higher spread of power providing more mid range RPM up through the red line. They come with factory installed, streamlined and internal tapered billet aluminum end caps that have recessed fasteners. The oval cut outs are a sign of the true craftsmanship that went into the design of these pipes. Kerker Stout 4" slip-ons, like their name suggests, are not a wimpy pipe. Hand-crafted for your riding pleasure, they provide a bold, strong power curve from mid range on up with a 9.6 (17%) BHP and 9 (12%) ft.lb torque gain over stock (measured on a 2010 FLH). Kerker Stouts are 97dB(a) (per SAE-J2825) or 5dB(a) over the stock mufflers on US Domestic models with that classic Kerker, deep, heavy rumble. Sold in pairs.