It's as thin as a credit card, and is protected against losses. If you lose the Coin wallet, it's connected to your phone via Bluetooth and alerts you when you've left it behind. You can also lock your card at a distance.
The Coin card comes with a card swipe dongle that connects to a smartphone or tablet. Swipe the cards you want to save to Coin, and the app updates the card.
It stores information for up to eight cards of all different types: credit, gift, debit and membership cards. You just select which card you're using on Coin's digital interface, and it mimics the card you've chosen. Then swipe.
The device works through magnetic memory -- the card remembers the magnetic swipe of the cards you install in it. Though the target consumer price by its planned 2014 rollout is $100, the prototype cost $1000 to develop.
And there are still some uncertainties to sort out. Since it's connected to your phone, if your phone runs out of battery it could disrupt Coin's functionality. And people will still have to trust the company with all their credit card information, which the company says will be encrypted and secure.
Coin is a Y Combinator-backed San Francisco startup led by Kanishk Parashar, who has worked on a number of mobile payment technologies including PayPal.
The company sold pre-orders at $50 to raise funding up to $50,000, and they reached their goal within 40 minutes of going on sale. It's set to cost $100.