Stainless Works offers two styles of kits; one is the butt-weld kit while the other is a slip-fit kit utilizing clamps. We choose to go with a butt-weld kit. Whichever way you choose to weld up stainless tubing one thing is for sure, you must use stainless filler rod. If not, the tubes will retain their natural color while the welds slowly rust away. I choose to TIG weld the exhaust together with ER-308 rod.