These copper bars have similar performance properties to beryllium copper, but do not require special machining techniques. They’re often used for high-stress applications such as studs, welding electrodes, mold cavities, and electrical components. Even after collisions and frequent use, they maintain their shape. They conduct electricity, but not as well as purer copper, such as 101 copper. Using them in extreme temperatures won’t change their mechanical properties, but you can process them with heat treatment if you wish to alter their properties. They’re RMWA Class 3, which is a class that’s commonly used to seam and spot weld stainless steel and other electrically-resistant materials. When used outdoors, these bars won’t rust.