FMF Fatty Pipe Expect bottom power and meatier mid range with an impressive top end gain of about 10% to 12% horsepower gain. This is real bolt-on power! The patented FMF Fatty Pipe is far and away the most copied power enhancing exhaust pipe in the world. The Fatty is computer designed and dyno tested giving each dirtbike model specific power gains. The Tru-Flo manufacturing process ensures quality fitment resulting in optimal performance. Fabricated from sturdy 19 gauge US steel, the Fatty is known for its all-around power gains from bottom to top. Nickel plating provides a durable easy cleaning finish. It\\\'s no accident that the Fatty Pipe is one of the best selling aftermarket pipes.