2007-08 Yamaha YZ450F Slip-On Exhaust Systems (w/ Stainless Steel Tubing): With the patented use of magnesium, aluminum and stainless steel, and hours of testing 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. 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.