Safety cans provide convenient and safe containment of a variety of fluids during transport and storing. Safety cans such as gas, diesel, and water cans or jugs often come in universally recognized colors that denote the liquids inside. Gas is most often red, diesel is yellow, and water is commonly blue or white. Many varieties include special spouts for safe pouring and filling. Additional supplies such as oil safe stretch spouts enable precise filling and pouring of liquids. The two most common safety can construction materials are rustproof polyethylene and galvanized steel.