For unmodified aftermarket exhausts Designed to pack all mufflers with core diameters between 1-3/4" - 2-1/4" and shell circumferences between 12" and 13-1/2" Measure the distance around the outside of the muffler's shell to determine its circumference If the muffler has been modified from the original length and falls between lengths available, order the next longest cartridge available for your muffler Made in the U.S.A.. PACKING PILLOW COMP 15"