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 3 X - pipe with 4 - 18 center to center dimensions, expanded on inlets to 3 ID. Length can be made from 18 to 36. These are TIG welded for strength and durability. These kits come with a lifetime warranty and proudly made in the USA.