Brass is an alloy composed of copper and zinc. Brass composed of copper and zinc is called ordinary brass. If it is a variety of alloys composed of two or more elements, it is called special brass. Brass has strong wear resistance and is often used to manufacture valves, water pipes, connecting pipes for internal and external air conditioners, and radiators. The exact properties of different brasses depend on the composition of the brass alloy, especially the copper-to-zinc ratio.