I received my unit Friday and used it right away Friday. Seemed like a 30 min session relieved my right shoulder ache for the rest of the night. Used it again today, Sunday, for a 30 min session after my shoulder started aching from using the PC too long, and again, it seems to have relieved the ache. What a great form of relief for such a small price. And no need to make an appointment at P/T. So convenient to use it at home when needed.