I picked up one of these and it works great! It's strictly a charger and DOES NOT have a built in battery. You can charge anything via USB as long as there's enough sunlight.

NOTE!

Placing panels in front of tinted windows is not recommended. It will impact the performance of the unit.

Charging my Verizon MiFi without any issues.

My YouTube video overview of the product:

Quick review/first impressions of this solar USB charger. For full details of the product, please see: http://www.ianker.com/product/71ANSCPS-B145A Amazon: http://amzn.com/B00E3OL5U8 Specs: Rated @ 14W total power/Two 5V USB ports @ 2A As noted in my video, I never saw the unit produce that much power, but there are a lot of variables involved in power output, especially with solar and USB.