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 4-1/8″ 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.