Helps prevent car theft and provides credit card protection Prevents thieves from tracking and transferring signals from your smart car key Helps prevent car theft and provides credit card protection Prevents thieves from tracking and transferring signals from your smart car key Blocks WiFi (2.4 and 5 GHz), Bluetooth, GPS, RFID, car key signal, etc. Simply placing your key and your credit cards into the closed faraday bag will prevent your car key signal from being accessible by thieves. Protecting your car at all times.