Chromium is actually the metal behind stainless steel. If a certain amount of chromium is added to steel, it will qualify as stainless steel. One of the best benefits to having stainless steel is that it is so resistant to corrosive action, this is because of the thin protective coating it has from its chromium content. The use of this metal has become a necessity for systems, especially the medical industries. Stainless steel parts and products can be found in cars, airplanes, appliances, kitchens, and factories. Depending on the purpose of the steel, various amounts of nickel, and other metals are used. The steel is often made to be non-heat-treatable or heat-treatable. Various widths, thicknesses and hardness levels are also used. These combinations determine the grade, quality, durability and prices of the steel.