These reusable replacement electrodes are the standard extra, extra, large electrodes supplied with the Wireless TENs units. They are fabric backed for strength and come with a plastic film to protect the adhesive surface when not in use. A single XXL electrode is required for each receiver module. 8 5/8” x 3 3/4” Please Note: HiDow is updating the design of most of their electrodes. They will be black in colour and a slightly a different size/shape as the blue stock runs out for each size.