The Beurer EM 29 2-in-1 Knee & Elbow TENS (Transcutaneous Electrical Nerve Stimulation) device is used to help combat pain in the knees or elbows without the use of medication. The universal cuff fits either knee or elbow and is adjusted to fit snugly and comfortably.This TENS device uses water contact, conductive carbon electrodes to carry out the treatment, so does not require gel or replacement electrodes. There are four pre-programmed applications as well as 20 intensity levels so that you can select or adjust to the best fit for you, even whilst a treatment program is in progress.