Question for the manufacturer. Thin film solar panels are made by other manufacturers. This is the kind of solar panel the average person could afford. Check out "Allpower 100-watt portable, folding solar panel" for backpacking with power bank. 

Yes, even when it is cloudy, it works, though never as well as in direct sunlight. I used it for 2 weeks on a Philmont trip, and it kept my devices charged. I still recommend a power bank instead of a direct connection. They just work better. I changed up the power bank, and it provided all the power to the rest of my devices. My DJ OSMO Action and my inflation device.