Review (1/5): Defective device
My device was zapping on contact with the skin even when it was set to zero and it felt quite strong. I tried using less salt, less water etc but nothing seemed to work. The controller knob was definitely not functioning. I burnt my skin even when I used at zero. You can see the scabs on the picture. I followed the instructions and left it on only for 15 seconds. Was too painful so I decided to just return it.