Transcutaneous Electrical Nerve Stimulator, more commonly referred to as a TENS unit and pronounced tens, is an electronic device that produces electrical signals used to stimulate nerves through unbroken skin. It is usually applied to the skin using two or more electrodes. A typical battery-operated TENS unit consists of a pulse generator, small transformer, frequency and intensity controls, and a set of electrode lead wires.
TENS is considered a method of pain management, and has a wide following for use in obstetric care particularly labor. Nevertheless, there is little data on its actual efficacy, and many obstetricians maintain that it is ineffective.
In palliative care and pain medicine, TENS is occasionally attempted for neuropathic pain (pain due to nerve compression). Although results are modest, some patients benefit from this approach. To generate more conductivity from the electrode to the skin a cream should be used. The position of the electrodes on your skin can alter which muscle is stimulated.
There is a secondary market for TENS units in the BDSM community, where the units are used for erotic play involving electrical stimulation.
Electrodes should never be placed near or on the eyes, neck, or on an open wound or cut. If placed on an open wound, the veins in your body will serve as wires sending a mircoshock directly to your heart, sending you into ventricular fibrillation. Also a TENS unit should not be used if you have a pacemaker in you, as it will interfere with the electrical structures on the pacemaker.