Rectangular tube, commonly referred to as “rect tube” is hollow tube in the form of a rectangle. Rectangular tube is specified using three dimensions, the lengths of both unequal sides and wall thickness. Rectangular tube is available in carbon and alloy steel, stainless, and aluminum. It is produced in the same process as square tube, typically by feeding strip coil through a series of dies where it is formed and welded. Carbon steel rectangular tube lengths run through 60 feet while stainless steel square tube commonly is carried in 20-foot lengths with some sizes available in 40-foot lengths. Aluminum rectangular tube runs anywhere from 20-foot, 21’1”, and 24-foot lengths depending upon the alloy.