Adafruit mifare classic 1356mhz rfid nfc cards tags and fobs 1kb adafruit 363 the adafruit mifare classic 1356mhz rfid nfc keychain fobs can be read by almost any rfidnfc reader that can handle isoiec 14443 type a cards with 1kbytes of stored data the fobs also have a permanent 4 byte id burned into each one so that you can uniquely identify them they support up to 100 000 re writes we also supply a suitable reader pn532 nfc rfid controller breakout board 73 5294 adafruits