RFID Smartphone Card Wallet. Many new credit cards contain Radio Frequency Identification chips which offer convenient scanning and information sharing at the expense of security and privacy. This protector will block RFID signals and protect valuable information stored on RFID chips from unauthorised scans or unwanted readers. It has room for 2 cards or IDs. The adhesive tape on the back allows you to fix the wallet to smartphones with a flat back. Aluminium foil.