Stainless Headers Mfg., Inc. lightweight race mufflers are made of 304 stainless steel and purge tig welded for optimal performance. These stainless race mufflers are performance proven and stand up to the most extreme conditions. Ideal for high horse power drag racing applications such as side exit muffler installations. Packed with a tough stainless steel scubble and purge tig welded, these American made race mufflers are the ultimate in performance and quality. This muffler is sized with an inlet/outlet diameter of 3" OD and a muffler body of 3 1/2” OD X 4” long and a 6” overall length