I bought the Tens unit for my husband because he constantly has back issues mostly relating to two dogs pulling him while walking or working weights at the gym. Our Weimeraners see rabbits, birds, etc., and decide to go after them while on a lease. this is a jolt to his back. I have had the TENS for a couple weeks asking him to use it and finally after prodding he let me put it on his back. Needless to say, he has now told me to order two more units. These are more powerful than the ICY HOT Tens and after a couple pushes of the power button, he’s asking me to turn it down. He wore the unit for about an hour and forgot he had it on! It helped the muscle relax and was able to play golf with no issue or pain. I’m now ordering two more!