Half-oval shaped electrodes with metal press-stud connection, compatible with Boots TENS units including Boots BT2 (Product code 20-26-465) and Boots Compact TENS. Boots electrodes product code 14-63-942 Each pad measures 50mm x 50mm (2" x 2"), and comes in a pack of four, with Instructions for application. We supply three packs together, so you will receive twelve pads altogether. Each set of four pads is sealed in a separate packet to retain freshness and hygiene until the moment you choose to open them. All TensCare electrode pads are hypoallergenic and extremely high quality. Although it depends very much on your skin type, the climatic conditions, and general use and abuse, your pads should typically last 15-30 applications.