2007-08 Yamaha YZ450F and 2007-08 WR450 M-7 Stainless Full Exhaust Systems(Stainless steel Piping): Sporting a stainless steel header & slip tube and a brushed aluminum M7 canister, we have come up with an exhaust system to win races. Increased throttle response, more power throughout the powerband, and lighter weight all add up to a winning combination for your YZ450F. Designed and built with painstaking care and attention to detail, Two Brothers Racing is proud to release our M-7 stainless full exhaust system for the 2007 Yamaha YZ450F.The Two Brothers M-7 off-road stainless/aluminum exhaust systems come complete with a U.S. Forestry Service approved removable screen type spark arrestor.