These baffles will reduce the sound approximately 2-3 decibels from the standard baffles, and offer a deeper rumble. There are two different sized baffles in the kit to work with the 2-5/8" (right) and 1-3/4" (left) slip-on inlets for the Vance & Hines M8 designed Touring slip-ons Includes mounting hardware Made in the U.S.A.. BAFFLE QUIET 17+ EL400M8