Crystal card is a highly personalized new type of RFID smart card, with a crystal clear and parent appearance, strong three-dimensional sense, and dustproof, waterproof, and vibration characteristics. Scope of application: Patrol system, attendance system, access control system, one card system RFID identification field. Size:31.5x28mm Chip:NTAG213 Storage capacity:148 bytes Working frequency:12.00-14.50MHz Number of erasures:10000 Data storage:5 years Reading and writing distance:1-10cm Support protocol:ISO14443 The product appearance and printed words depending on the batch, but this does not affect use. Colour:Green Material:Drop glue Package Contents: 20 * NFC Smart Card Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.