Rat trap muffler, Made from 304 stainless steel for maximum corrosion resistance. This muffler has 3-1/2" ID center inlet / outlet with a 2-1/2" core. Exclusive louvered core creates a sweet "Street Rod" deep tone that is not overly aggressive. It is 3-1/2" body with turn down style tip (24" overall length), Mill finish. These are TIG welded for strength and durability. These kits come with a lifetime warranty and proudly made in the USA.