RFID blocking sleeve is designed based on Faraday cage principle, NFC / RFID communication is a kind of radio communication technology, the signal transmission uses the electromagnetic alternating field, this electromagnetic field spread in the Faraday cage principle protective card sleeve surface will be "Transparent" to the other side of the ferrule, and in the housing of the ferrule, no alternating electromagnetic field can be detected (since the electric potential is equal everywhere and there is no moving charge according to the Faraday cage principle), the smart cards inside the sleeve will not respond to external electromagnetic field communication.

The RFID chip in the blocking sleeve can not absorb the power transmission from the RFID card reader device, so there is no power to start the electronic structure that requires power internally, so that the RFID device can not obtain the smart card information even near the IC card in the protection card sleeve, Effectively ensure the security of your smart card.