This is a blank 13.56MHz RFID/NFC keychain fob - often used for keys but also an easy way to tag something. The tag contains a small RFID chip and an antenna, and is passively powered by the reader/writer when placed a couple inches away.
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.
1 x 13.56MHz RFID/NFC Clear Keychain Fob - 1KB
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