to produce. However, immune system reaction to nickel is a potential complication of 316.[1][2] Implants and equipment that are put under pressure (bone fixation screws, prostheses, body piercing jewelry) are made out of austenitic steel, often 316L and 316LVM compliant to ASTM F138,.[3] 316 surgical steel is used in the manufacture and handling of food and pharmaceutical products where it is often required in order to minimize metallic contamination. ASTM F138[3]-compliant steel is also used in the manufacture of body piercing jewellery[4] and body modification implants. 440 and 420 stainless steels, known also by the name "Cutlery Stainless Steel", are high carbon steels alloyed with chromium. They have very good corrosion resistance compared to other cutlery steels, but their corrosion resistance is inferior to 316 stainless. Biomedical cutting instruments are often made from 440 or 420 stainless due to its high hardness coupled with acceptable corrosion resistance. Long story short, not all "surgical stainless steel" is safe for initial or healed piercings. Your piercer should be able to show you metal certs from the manufacturers they use and explain these details. For further info on safe materials for piercing, please visit safepiercing.org. Allergic reactions, when they occur, are rarely due to the stainless steel but from other factors (most commonly from mechanical irritation or harsh cleaning products). Allergic reactions typically include itching, redness, and swelling, with a discharge of clear fluid that is not lymph. The element in stainless steel that causes allergic reactions in some people is nickel. Polishing the jewelry to a mirror like luster results in a protective layer of chromium oxide which reduces the migration of the Nickel content into the tissue. One disadvantage of steel is its weight. For larger pieces of jewelry this can be a problem as it can cause tension in the body tissue, and also unwanted stretching or tearing of a piercing. In areas with low blood circulation, such as the earlobe, this can be potentially dangerous. However, with smaller jewelry, there is no need to worry. Another downside is its tendency to become very cold during winter. This can cause problems; due to this, many change their jewelry to others made of horn, bone, wood, plastics and glass during winter. Steel body jewelry may be sterilized in an autoclave. The two most common standards that apply to body jewelry made of steel are ASTM F138 and ISO 5832-1 which describe