Highly Recommended!
This unit has been a lifesaver! It works amazingly well. It holds a charge for a long time. I had cervical fusion surgery 6 years ago and had residual deep muscle pain in my left shoulder ever since.  After using this unit several times the pain is virtually gone.  Now I only seem to need it once a month or so.  My wife is a runner and uses it to stimulate the muscles in her legs during longs drives, and it works wonders for her, too.  I typically don't set it above 5-7, even though it goes up to 20.
Rating: 5 stars