While object products are rack-plated or barrel-plated according to shape and size, reel-to-reel (hoop) plating for continuous plating of long hoop materials and coiled materials plays an active part because of demands for mass production & high-speed production of micro electronic parts, such as connectors. Specifically, plating, flowing in the order of feed reel → plating process → take-up reel, offers excellent mass productivity.