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Master card? 'Coin' combines debit, credit and others into one

The Coin card is no larger than an ordinary credit card.Coin

If you've ever been frustrated by the number of cards you have to carry on you at all times, from personal debit to work credit to gift and loyalty cards, this high-tech new mega-card might be for you. It's called Coin, and it works with your smartphone to combine all your cards into one.

Coin works by keeping the magnetic information for each card in its memory, and rewriting its own magnetic stripe to imitate whichever you choose. You get the card data in there by swiping it through a little dongle for your phone.

You can toggle between up to eight cards with a button on the card itself (carefully designed so it can't be hit on accident), and switch out expired or used-up cards using the app. For credit rewards hounds, gift card aficionados or anyone who just finds their wallet is too bulky, this could be a great way to simplify things and save space.

It works in ATMs, gas station machines and basically anywhere your normal card works. And don't worry, it's not going to tick off your bank — they won't even notice, for one thing, and Coin checked ahead of time to make sure this whole process is legal and approved.

The card even has a built-in Bluetooth low-power chip, and will alert you on your phone if you've left it behind at a restaurant or if it's gone too long without detecting the phone's presence. That sounds useful, but it has a serious problem: If your phone dies, so does your card.

It's an unintended consequence of the brave new world of connected devices — they tend to have a single big point of failure, whether it's your phone, a data connection or just limited battery life. Luckily, you can turn off that feature on the card if you're planning a long phone-less vacation or know you're about to run out of juice.

Coin should be hitting the streets in the summer of 2014 — for $100, which for many might be a bit much for the amount of convenience it provides. But if you pre-order one, they're $50, so if it strikes your fancy or you think it might make a good for someone (next year, of course), now's your chance to get it for half off.

If you're in Canada or a place where chipped cards are common, however, you'll want to hold off. Other payment systems are planned, but not for a while.

Devin Coldewey is a contributing writer for NBC News Digital. His personal website is