100 PCS Aluminum Foil RFID Blocking Credit Card ID Bank Card Case Card Holder Cover, Size: 9 x 6.3cm (Black)

1. To prevent strong electrostatic interference
2. To prevent the strong magnetic field damage
3. To prevent others from malicious reading, stealing your personal information
4. To extend the effective life of smart card
5. Small sieze, portable to carry
6. The colors are bright and eye-catching