In TENS units T.E.N.S. stands for Transcutaneous Electrical Nerve Stimulation. Pain, whether chronic (long-term) or acute (short-term, often from surgery or trauma), can be relieved through a variety of methods including drugs, topical ointments, surgery, and electrical stimulation. T.E.N.S. devices deliver mild electrical pulses through the skin to stimulate the cutaneous (surface) and afferent (deep) nerves to help control pain. Unlike drugs or topical ointments, T.E.N.S. does not have any known side effects.