Gas metal arc welding (GMAW), sometimes referred to by its subtypes, metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. (GMAW – Gas Metal Arc Welding) is the most common process use in home shops, small businesses, manufacturing and metal fabrication applications. A constant voltage, direct current power source is most commonly used with GMAW, but constant current systems, as well as alternating current, can be used.