>>14489257foil hats don't work unless you scrape the coating off (the foil is meant for food, there is a coating to keep the aluminum from oxidizing) then replace it with a conductive coating. After that, it has to be grounded somewhere. EM waves are exactly the same as electricity, the foil has to conduct them somewhere or they easily pass through or reflect depending on the angle. It's a lot better to use copper tape instead of aluminum, the best would be a solid steel helmet with a grounding cable. You'd look ridiculous and the cable would obviously have a finite length.
Your link is garbage, honestly, it makes zero sense to claim something passive like foil 'amplified frequencies'. If they created an amplifier that magically doesn't need energy from anywhere else, they would be richer than Bezos right now.
