The electrodes for the Tig differ in color: Red Color 2% Thorium: for Stainless Steel Blue Color 2% Lanthanum: Specific for Stainless Steel Green Color Pure Tungsten: Specific for Aluminum Gold Color Tungsten with 1.5% Lanthanum is possible use with AC / DC current it is used with high alloyed and non-alloyed steels, aluminum magnesium alloys, titanium, nickel, copper etc.-Gray color with 2% Cerium Oxide Specific for welding Aluminum and Stainless Steel.