Smart Relief's electrode pads come in several sizes based on your particular needs: small (1.7"x1.2"), large (3"x1.8"), and jumbo (4.4"x2"). Each electrode pad is pre-gelled (no more mess!) and self-adhesive. Our pads are flexible and lightweight so they'll contour around joints and won't fall off from natural movements. Smart Relief's TENS replacement pads are universal and are compatible with all Smart Relief devices or any TENS unit that accepts a snap connector. With proper maintenance and cleaning, each reusable pad can last many months of repeated use.