These support tubes are made of brilliant polished 304 stainless steel. They have good surface hardness and do not score from clamp binding screws. Tubes are 1/2" (13 mm) in diameter and are hollow, reducing weight to half of solid stainless steel rods while maintaining all the advantages of the stainless steel. The walls are 1/16" (1.6 mm) are thick, strong, and do not sag. The ends of each tube are capped with polyethylene tight fitting end-caps.