What it is: A slender card and cash pocket that holds as many as eight credit cards and attaches like a sticker to the back of almost any cellphone. Designed to replace your wallet when you just need to tote a few credit cards and cash, it is compatible with all iPhone and iPod Touch models, almost every Android phone, most BlackBerry devices and almost every Windows phone. It attaches to phone cases, except for those made of soft silicone or rubber. Available in black, steel and eggplant. If you occasionally misplace your wallet, CardNinja suggests it will be easier to find when it's on your phone because iPhone, Android and BlackBerry phones all have a "find my phone" app that would lead you to your CardNinja wallet.
The good: The CardNinja enables me to zip through airport security with my ID in the CardNinja and my boarding pass on my phone. Even when I have a paper boarding pass, it's handier to reach for my iPhone with the CardNinja than to dig for a wallet. I regularly abandon my wallet for trips to the gym, store and other places where I may not want to schlep a purse. As the company promises, you can store a few credit cards and cash, turn the CardNinja upside down, shake it and nothing falls out. Although the manufacturer doesn't recommend frequently moving the CardNinja from one phone case to another, I peeled it off one case and moved it to another without any problem.
The bad: I'd like to see RFID-blocking technology to prevent identity thieves from possibly scanning my credit cards.
Available from: cardninja.com and amazon.com.