Adafruit Micro NFC/RFID Transponder - NTAG203 13.56MHz [ADA2800]
This tiny micro NFC/RFID tag is super small, and contains an NTAG203 chip plus antenna. It's super tiny, flexible and a great way to DIY an RFID or NFC device if you're interested in designing your own ring, wearable or whatever other tiny device with near field communication incorporated. Contains 144 bytes of read-write accessible memory.
You can use this with our PN532-based RFID reader breakouts & shields, and will work with all the latest cellphones or tablets that have NFC built in. Note that since the antenna is so small you'll need to put the tag right up against the device that's reading it. Can be used to control a cellphone with commands, URLs, unlocking, etc.
Learn more about RFID / NFC products and projects on the Adafruit Learning System.