A tinfoil hat would be much cheaper. It's what they're claiming the product is - a jazzed up tinfoil hat. Only they're doing it wrong as they're claiming that the tinfoil blocks radio. They should have referenced Faraday to make their tinfoil hat sound more scientific so they could charge more for it.
Did you not read my answer, they don't claim it stops EMF waves but builds the bodies defences.
https://forums.overclockers.co.uk/posts/33681016