&&This product, part number 2000, is extruded aluminum alloy pipe. It is seamless, in 19’ (5.8 m) lengths, with outside diameter of 25.1 mm, inside diameter of 21.5 mm, 1.8 mm wall thickness, and is powder-coated on the outer surface. The specifications found on Airpipe’s website identify that it is made of 6063 aluminum which is an aluminum alloy. It is used in the construction of air line systems.