Why do you need a Faraday bag Modern keyless fob have an ID chip that can receive radio signals from the car. When the vehicle is within range, the key fob is recognized and the doors are unlocked. A keyless ignition system works the same way - allowing the car to start when a key fob is detected in the car. Criminals can exploit this through wireless relay attacks. By using an RF relay amplifier, the signal from the key fob can be picked up and transmitted to trick the car into thinking the key fob is present. This allows access and theft from the cabin or trunk – and, in the case of a keyless ignition system, theft of the vehicle itself. Open size: 13.2 * 12.9 cm Closed: length 8 cm, width 12.7 cm