For this EMS machine, I hesitated at first, but it has very powerful functions. I had residual middle and lower back pain after severe cramps, which did a great job in relieving the pain. It has two independent channels, so you can work in two different areas at the same time. It is rechargeable and can last for several hours. On the first day I used it, I ran for 90 minutes at a time and did it many times that day.
