Shield: Signal Proof Headwear by Shield Apparel %u2014 Kickstarter. If you have ever worn a tin foil hat to keep away aliens, do I have a product for you. This headgear purports to block all EM signals from cell phones, microwave ovens, Bluetooth transmissions, and other stuff that the conspiracy theorists say will fry your brain. Of course, there is no real scientific proof of this phenomenon; but, hey, we live in an age of fake news anyway, don't we? Jeez.