The Fischer requires a prescription because it's in the USA. I know it's stupid.
I kind of relate that to contact lenses, and how you need a prescription for them. I believe that once you pay to get your eyes checked and figure out your contact numbers, you should be able to freely purchase the contact lenses that you need. I mean, how much damage can I do to myself with contact lenses compared to, let's say, pain killers.
Since iontophoresis is a medical device, the same precautions are "needed."
In my situation, my doctor didn't believe in iontophoresis so I couldn't get a prescription. I took matters into my own hands and decided to purchase the Idromed 4 @
http://www.iontophoresis-device.com/
As far as going up to 50mA with the Fischer, I think that is excessive. I treat my hands at 10mA and my feet at 18mA. Even at those respective currents, the tingling sensation is quite evident. Unless you're a Hobbit or you wrestle bears all day long, going up to 50mA would be painful.
As for the depth of the trays: I put the water up to where the hair grows on top of my hands. That way, the finger tips and sides are submerged. My hands have been completely dry, including sides and fingertips. Also, Vaseline is your best friend here. I rub it on top of my hands to avoid burning. On my feet, the water goes over the toes and up on the sides. The bottom of my feet are completely dry but the sides tend to sweat a little bit. The feet will be the hardest to treat.
Hope this helps.
[/b]