11/02/2011 01:29 pm ET | Updated Jan 02, 2012

Square's Card Case App Lets You Pay Just By Saying Your Name

Thanks to the latest app from Square, you can now pay for things without your wallet, your credit card or even your hands.

Square, a mobile payments startup founded by Twitter co-founder Jack Dorsey, has released a new version of its Card Case app that allows users to pay for goods at certain stores just by saying their name.

"Try it! It feels like magic," Dorsey tweeted Wednesday.

Here's how it works: the latest version of Card Case, currently available only on iOS devices, uses the geo-fencing technology in Apple's iOS 5 operating system to recognize when a user is within 100 meters of a Square retailer and, when a user is in range, automatically opend the user's Square account for that merchant, so long as the "automatic tabs" feature has been enabled for the establishment.

With her Square "tab" already open, the user can then pay for her merchandise just by giving the cashier her name.

To prevent people from mistakenly charging goods to other people's open Square accounts -- say, if there are two "John's" both using Square at the same hip coffee shop -- Square will show cashiers the photos of the Card Case users next to their full names (Hint: use a nice, clear photo of yourself on your Square profile). (See image below)

Thanks to iOS 5's geo-fencing technology, the Square tab for approve merchants will automatically open anytime a user is within 100 meters of the retailer, meaning that there many be instances when a user's account becomes activated when she goes near, but doesn't stop at, a store.

A Square spokeswoman told The Huffington Post that Square currently has 20,000 merchants using Card Case in the U.S. Check out a demo of Card Case on Square's site here.