Like Oznog said, it's proper name is a TENS unit, not "tinge". And, I actually do know what function a TENS unit performs, but I dare say that many people reading this thread haven't a clue what it is, until now. For those of you who don't know what the acronym represents, see Oznog's post. As for what it does, it's a device used to stimulate nerves for controlling pain.
Yes, Nigel, I am very well aware of Google as a [reasonably] valuable resource. As a matter of fact, I use it on a daily basis, which (apparently) numerous posters do not.
My initial post was designed to allow the OP to elaborate on his post, as was the post from RusslK.
JB