I received Power Theory Credit Card-Sized 2500mAh Portable Charger, in exchange for honest review from Tomoson. I liked this charger because the USB cord for charging is built in. You charge the power bank with a cord provided, on the port on the outside though.
With the product, you receive the USB charger, a micro USB cord for charging the device, and an adapter for charging an iPod. The charger takes a few hours to fully charge. I have used the charger to charge my phones and tablets. I just have to remember which port is which. Blue power cord is for charging your phones, tablets, and other devices. Outside port is for charging Power Theory.
You can purchase the product using the link above. Power Theory's portable charger using the link above. The charger is prime eligible.