All tubes are CNC mandrel bent for optimal flow for all bends in this x-pipe. Made from 304 stainless steel for maximum corrosion resistance. This 2-1/2" X-pipe with 4-1/8" center to center dimensions, expanded on inlets to 2-1/2" ID. Length can be made from 18" to 34". These are TIG welded for strength and durability. These kits come with a lifetime warranty and proudly made in the USA.