Shields 100dB. Blocks frequencies between 800MHz – 5 GHz. Blocks CDMA/GSM/DCS/PHS/3G/4G. Blocks Wifi 2.4 – 5 GHz, Bluetooth (2.4GHz), and GPS (1-2GHz). Blocks RFID / NFC 125 KHz & 13.56 MHz. Blocks Carrier, hardware, and OS agnostic. Wireless signals (radio frequency or RF) are used in communication for your phone, tablet, car radio, computer, credit card, etc. The electronic transmission of this data is done wirelessly and poses many problems to your security and privacy. It makes all of your information open to be intercepted. Radio-frequency identification (RFID) is the use of a wireless data transmissions attached to an object, such as your credit card or passport. This information can be lifted, skimmed or scanned by anyone with simple technology. Near Field Communication (NFC) is just like RFID except it can communicate both ways making data transferable to and from a chip. This is what Google Wallet and Apple Pay utilize for transmission of your credit card information at a point of purchase.