... speed, lower cost, no limit for the engraving area, can engraving whatever plane or bend surface, No noise, ... less than 1/10 price compare with the laser engraving product, besides, with clearly, enduring, no change ... , but for groove plating, hanging plating, or roll plating, it suit for all noble metals plating ... etc. it not only for hanging plating, but roll plating as well, with suit for all products ...