I've never felt great about any other EMF protection as far as being truly protected from the cell towers in close proximity to my house, until I tried out the Phi devices. I don't have a ton of cell towers near me (<100), but I am within <1 mi of at least 2. I can actually see one of them from my bedroom window.
I have a larger home, so I keep the big Phi device in the center of my home, the mid-sized Phi device plugged into my office wall, and the small portable Phi device in my nightstand at night and in my handbag during the day if I'm away from home.
Before plugging these things in, I really could feel the radiation from the electro smog of the cell towers. I'd get this intense dehydration that I couldn't fix with electrolytes, which would often lead to a migraine. I would also get a sort of dizzy, neurological, electrical feeling along with blurred vision/difficulty focusing my eyes. I already had trustworthy protection from WiFi and dirty electricity, so I had a strong suspicion my symptoms were from the cell towers, specifically.
After plugging the Phi devices in, I realized within weeks I wasn't having any of those symptoms anymore. It's crazy to think about all of the time I lost from being sick because of these cell towers.