Powercore 2.1 Silencer. FMF is about moving forward...faster. The all new Powercore 2.1 silencer is proof FMF is totally committed to 2-stroke progression. FMF loves 2-strokes, they ride 2-strokes, and they are devoted to delivering superior power to the 2-stroke faithful. Race-tested, smooth power curve throughout the RPM range. Engineered to assault today's tracks built to favor 4-strokes. Larger diameter canister for more tunability and longer lasting packing life. Delivers a crisp, notable sound. Lighter than stock. Optimally designed to complement performance of FMF pipes; works and fits FMF or stock. Note: For closed course competition use ONLY. Not intended for street use. Detailed Specifications: Type: Silencer. Configuration: Single. Construction: Aluminum. Finish: Natural. Midpipe: N/A.