FMF Powercore 4 race inspired price point muffler made for maximum power output. FMF Aircraft quality extruded aluminum canister with stainless steel components. FMF Spark arrestor included. FMF Racing has been coming out with new Exhaust systems for dirt bikes all the time. Like the FMF 4.1 with the Mega Bomb and new FMF power core slip-on. Nicoll Racing has been installing FMF full system Motocross Exhaust on all our race Bikes with great power gains. Try a new FMF Powercore 4 on your Dirt Bike.