What is a Faraday Bags? It is a structure that blocks the passage of radio signals. Why do you need the Faraday Cage? Modern keyless fobs carry identification chips that pick up radio signals sent out by their car. The vehicle recognizes the fob when it's in range and unlocks the doors. Keyless ignition systems work in the same way - enabling cars to start when the key fob is detected in the cabin. Criminals can exploit this via a wireless relay attack. Using a radio frequency relay booster, it's possible to pick up and then transmit a key fob signal to trick the car into thinking a fob is present. This rfid key fob protector enables entry and theft from the cabin or boot - and, in the case of keyless ignition systems, theft of the vehicle itself. Thanks to its 100% signal jamming capability, faraday bag can completely isolate your fob to make such attacks impossible - giving you complete peace of mind as a key fob protector against data loss. How does the faraday bag for key fob work? Our car key signal blocker make your cars safe by stopping signals being sent or received by your key fob or any other device containing data. Remove your key from the rfid bag and signal reception is restored immediately, enabling normal usage. Attention: 1. Please make sure your vehicle key fob is put in to inner layer since only the Inner layer blocks signals 2. The size of these faraday pouch is designed for suit for mobile phones. 3. Please do not wash the rfid pouch for key fob; keep the interior dry, or it may lose signal-blocking function