Its where u cut the exhaust tailpipes off right behind the muffler and either weld or clamp "dumps" which just turn down towards the ground. You lose a little weight that way, but gain alot of sound, but if u like that like me then its cool. I had dumps with factory exhaust save weld in flows..sounded pretty loud but might be a little too loud with an offroad pipe. I put my tailpipes back on and then changed the midpipe. Id be curious how it sounds with it now. I think having no tailpipes makes the car look tougher..but tailpipes look cool and give it a little better tone just not as loud. Id go back to dumps but i like the looks of tailpipes more so. I want the SLP catback, then be plenty loud enough for me :drool: