= Bitcoins in physical form.
URL = http://www.bitbills.com/
"Bitbills are the first and only bitcoins in physical form.
Bitbills let you store and transfer bitcoins in person, just like cash. Also, Bitbills aren't vulnerable to digital attacks, making them the safest way to hold and use bitcoins.
Each Bitbill securely locks bitcoin data between layers of the card. If you would like to get non-physical bitcoins again, you can easily convert your Bitbill or trade them for digital bitcoins."
- how they work, http://www.bitbills.com/how