The large 3.5" diameter Street Cannons provide free exhaust flow with just the right amount of back pressure for a smooth ride. Designed for international markets requiring ECE certified silencers. Installation requires separate purchase of Muffler Clamps P/N 65900012 (Item 2) or P/N 65100123. The exhaust end caps must be ordered separately. Fits 2018 FXBF FAT BOB FXBFS FAT BOB 114.