STUD ADHESIVE PADS - The studded adhesive electrode pads are perfect for back pain and a smaller area for targeted relief. These electrodes are hypoallergenic and reduce the risk of reactions. REUSABLE - Each electrode is reusable for 15-25 applications and made with a high-quality, long-lasting hydrogel. To extend use, ensure electrodes are stored in their packaging. UNIVERSAL COMPATIBILITY - For fast pain relief, use these adhesive electrodes with almost any TENS machine on Amazon with a 3.5mm stud connector to target back, joint, and muscle pain. CLASS 1 MEDICAL GRADE - These 5cm x 5cm electrodes have strong conductivity and are certified Class 1 medical devices. NHS TENS SUPPLIER - Med-Fit is based in Greater Manchester and is a UK-approved medical device company. We have supplied genuine TENS machines to NHS hospitals and pain clinics for 15 years. Every TENS machine comes with full after-sales support and access to professional advice from our therapy team.