This is an excellent back up power source, not very expensive and a good bug out bag item. I have one. You can use it to power iphones, ipads, or anything that can be powered by USB. Up to 2 devices at a time. I ran my ipad for 16 hours with this.
Think about it, long term power outages. The internet may very well still be working, but you need power for your devices so you can communicate and access the internet.
It's also a good practical item. It saved my butt while on a business trip.
Anker® Astro3E 10000mAh Dual 5V 3A USB Output External Battery Pack Charger for Smart Phones, Android Phones, PS Vita, GoPro; iPad mini, iPhone 5 (Lightning Cable not Provided); iPhone 4S, iPad; Samsung Galaxy S3, Galaxy Note 2; HTC Sensation, One X V S, EVO 4G, Thunderbolt; Nokia Lumia 920 900 N9; Motorola Razr; LG Optimus [4 cellphone connectors included, 0.6 inch slim design, customized for Apple & Android Devices]http://www.amazon.com/dp/B009USAJCC/ref=as_li_qf_sp_asin_til?tag=handgpodca-20&camp=14573&creative=327641&linkCode=as1&creativeASIN=B009USAJCC&adid=11HGA1BX13FJ74645341&&ref-refURL=http%3A%2F%2Fwww.todayssurvival.com%2Fmy-edc-store%2F