There is also a permanent 4-byte ID burned into the chip that you can use to identify one tag
from another - the ID number cannot be changed.
These use a ISO/IEC 14443 Type A chipset, which used to be the 'classic' NFC chipset. In ~2014,
the NFC forum decided not to support this chipset anymore, so newer phones do not support it.
This only matters if you're trying to use this tag with a phone/tablet.
13.56MHz RFID/NFC Plastic Nail (7:43)
TECHNICAL DETAILS
RFID chip specification:
1 KiloByte (8 KiloBit) non-volatile EEPROM storage
Built in encryption engine with 48-bit key
4 Byte unique identifier burned into the chip
13.56 MHz frequency
Tag specification:
Max Dimensions: 22.11mm / 0.87" round x 41.37" / 1.62" long
Head Dimensions: 22.11mm / 0.87" round x 4.06mm / 0.16" thick
Shaft Dimensions: 6mm / 0.23" round x 38.23mm / 1.5" long
2.32g
Works about 2" away from reader