Designed for maximum torque and power across torque curve Features a durable 16 gauge steel body with a lightweight aluminum rear end cap Includes U.S.F.S. approved, removable screen-type spark arrestor; replacement spark arrestor sold separately Bolts on to stock headpipe in minutes Repackable muffler body Optional Quiet Core Inserts available separately Made in the U.S.A.. EXHAUST RCM II S/O 450R