Tired of bulking up your wallet with several different credit cards, id cards, and transit cards? We found out a way to extract the key functional components from the Clipper Card, and mold it into a variety of wearable devices, including a small rubber plate, a waterproof aspirin band, and a breadboard bracelet.

Source: Transform the SF Clipper Card Into a Wearable: 7 Steps (with Pictures)

Ooh, that’s very cool! I wonder if it’d work with an Opal card??