The Rush Big Louie 4 in. muffler is a top choice for Harley-Davidson Touring Riders, four different sizes means you can order the sound that suits you best. Baffle sizes are measurements of the baffles diameter. That means the larger the baffle, the louder the pipe! The SB2 kit includes 2.50 in. right baffle and a 3.00 in. left baffle to keep the muffler from bluing due to high heat from the catalytic converter. Made in USa. NOTE: CLAMPS NOT INCLUDED ST3 2-1/2in. stepped baffles.