Review on 20X15In Faraday Bag For Laptops, Phones & Key Fobs: Fireproof, Water Resistant Anti-Theft Pouch With Hacking Blocker (Black) by Dezz Watson

The design does what is essential to block EMFs from any attempts to electronically access protected devices and in the unlikely event of an EMP protects against damage. One precaution, devices should be turned off (powered down completely) to prevent overheating because there is no air flow through the bags. The large bags (for laptops) are made of material that is virtually water proof. I don't intend to test that but I'm confident that water can't get in a properly closed bag. I have tested the key fob bag and can confirm that it is not possible to actuate car locks or ignition when the bag is closed, even when within inches of the sensors.