TENS is Transcutaneous Electric Nerve Stimulation for short. It works by disrupting the pain signals originating from the nerves near the pain spot, so the area that would normally be in pain is reduced to a mere tingling sensation. It’s like having a constant little massage at the point that causes you the most discomfort.
You can’t get one of these godsends without a prescription from your doctor. Further more, you can’t use the TENS unit to charge a battery or jump a car. It’s wise to only be used for two hour intervals at a time. A break must be taken in between, otherwise the electrode pads would get too hot, then you’d really have something to cry about.