I’ll be blunt. This is one device I have to have! Someone tries to take my Bio-Tuner is likely going to get a truckload of hell-fury.
The scientist who designed it (Dr. Robert Beck) was a genius, and also was involved in classified research involving such topics as magnetic, electrical, and radiation (such as radiowaves and microwaves) effects on mood and behavior. In other words, he was involved in studying defense against exotic weapons. (Look up wood pecker signal US embassy, and that might give you some background; never mind the sanitized article at wikipedia; the wood peck event happened and the effects are well establish.)
Basically, Dr. Beck knew what he was doing. He analyzed different cranial-electrical-stimulation devices from Europe, Soviet Union (Russia), and Asia. For the Soviets, such devices were important for them because during the cold war it was rumored their generals tended to drink vodka a lot. It was the cold war in the 1960s to 1980s, and they wanted their generals off alcohol and sober. So cranial-electro-stimulation (and I think some magnetic devices) were in use there.
For the SOTA device, the carrier frequency is 1000 Hz and it is modulated at 111 Hz. Endorphins are supposedly released at a frequency of about 90 to 111 Hz.
I use it for sleep problems. I have not used it for pain. If I did have pain, this is the first thing I would reach for. I’ve used their Bio-Tuner 9 and their Bio-Tuner Lite, as well as an earlier version called the Brain Tuner 6.
https://www.sota.com/default.aspx?page=Bio-Tuner
https://www.sota.com/default.aspx?page=Bio-Tuner-Lite
By the way, I’m sure you’re familiar with Dr. Beck. He’s one of the most famous scientists that you never heard of. You used that flash on your phone to take a picture, right? He invented the re-useable flash bulb. Flashbulbs of today are based on his invention.