In comparison to Thoriated (red) and Pure (green) electrodes, the E3 (Purple) electrodes are less harmful to the environment and not radioactive. They offer excellent arc starting and stability characteristics and consistent welding properties. Suitable for all applications in both DC and AC welding for steel, stainless steel, aluminum, titanium, nickel, copper and magnesium alloys. The E3 electrodes also offer an increased current carrying capacity and longer service life than thoriated or Pure electrodes. Pack of 2, 1/16\" x 7\" E3 (Purple) TIG Tungsten Use the E3 Purple tungsten electrodes in place of the discontinued red or green on steel, stainless, aluminum, copper and nickel.