Made of 75% tungsten for wear and arc-erosion resistance and 25% copper for electrical and thermal conductivity, these bars work well for electrodes in the electrical-discharge machining of tungsten carbide and other dense material. They’re RWMA Class 11, so use them for facings and insets for flash and butt welding dies, projection welding electrodes, and seam welding. Compared to RWMA Class 10, they’re more wear resistant because they contain more tungsten. They’re commonly known as Elkonite bars.