Digital artist Dhani Sutano designed this enamel ring with a built-in RFID chip from a London Oyster Card, making it the most convenient piece of jewelry we've ever seen. However, as the process behind making something like this and it's use is illegal, you might want to reconsider re-creating the piece. Check the artist out in the video below using it to enter a London metro station:

[via Vimeo]