These days having an extra battery or an external battery pack to keep the charge flowing to your Android device is never a bad idea. In most cases, smartphones may have a harder time keeping a charge that will last throughout the day, short of a few devices that have been released so far this year like the Xperia Z3, Galaxy S5, and the DROID Turbo. If you're on the hunt for a power bank though, you might want to take a look at this deal from Lumsing with their 10400mAh harmonica style power bank, which is now on sale through Amazon at $22.59. We did a review of this particular power bank which you can check out here for more details. What this provides is pretty straight forward, two USB ports to charge two devices at once, 10400mAh battery capacity, and a nice little carrying pouch to keep everything in one easy to find spot.