"Copper" is basically made of brass and is chrome-plated on the surface. It is well treated and can reach the mirror surface. Plus the price of copper, it will have a noble feeling. If it is not plated, the surface is very prone to patina. The use of such a plating layer is much more reliable than processing a layer of "paint" on the iron surface, but it also depends on the plating process, otherwise there will be a raw patina when not used for a few years. Because the price of "stainless steel" materials commonly used in sanitary ware products is much lower than that of copper materials, some manufacturers do not absorb the characteristics of stainless steel and copper, and the stainless steel materials are electroplated and counterfeited as "copper" materials. However, although the cost of plating stainless steel is not cheap, it is generally cheaper.