TENS Unit Silver Electrodes give you better performance for all TENS Unit & Muscle Stimulator Electrotherapy applications. These pads feature a durable white-mesh backing. We also use copper lead wires with special heads that help promote greater dispersion and prevent wire pull out. Finally, we use only the finest gel on the market today for greater reusability and superior performance. You simply cannot buy a better TENS Unit Electrode! ITEM CANNOT BE RETURNED IF PACKAGE HAS BEEN OPENED.