A type of DC arc welder which uses filler metal fed in the form of a spool of thin wire, and shielded by a flow of inert gas (CO2, Argon), instead of flux such as is used for arc welding. Very fast, much easier to use than a more general arc welder, with less heat buildup. Very good for sheet metal, due to minimal heat distortion. Harder to weld thick stock with, as welds are weaker due to poorer heat penetration. The modern choice for steel automotive body work, it can also be used to weld aluminum, if Argon is used as the shielding gas.