Louder exhaust does not mean more horsepowerBlown-out packing causes exhaust turbulence and increased back pressure, which reduces horsepowerRepack your silencer with this pro-quality, three-layer packing system and restore the power you've blown outAlso great for getting in compliance with new sound lawsKit contains 1/4'' thick 60'' x 20'' glass mat, 7'' x 20'' stainless wool, 8'' x 20'' stainless mesh, twelve 3/16'' rivets, and full instructionsMade in the U.S.A.