“Bought two of them, one started a extremely loud buzzing sound like something was loose inside it, the second one worked for awhile then the electric wire broke inside the cord cutting the power to it. They are not user repairable and you would have to crack the case open to replace the power cord if the mediocre warranty ran out. I'm still looking for a well made product that will relieve knee pain for me, but haven't located one yet. Wahl used to make a very good product. We had one that lasted almost 35 years, but finally gave out.”