I need a small solar source for my bug-out bags for my significant other and myself. This fits in a regular sized backpack. I did an early test of the built-in USB. Daytime but cloudy completely overcast day with some gray. Layed it out flat. Got a half amp on from the USB. I can fully charge my Garmin inReach satellite communicator in a few hours with that. Looking forward to testing it on a sunny day. Hope to get 2 amps from the USB.

Did a more thorough test with the raw solar output jack today. Ran it through a MPPT charge controller and charged a LiFePo4 battery. Measured current with a clamp meter. Oh YEAH! It was exactly what it should be. For my location (upstate NY), date (October), and time of day (1PM) , I got exactly what I was supposed to get ... even with the foldable panel just propped up at approximately the right angle. There is no doubt that this panel will produce 60 watts in the summer if you have an MPPT charge controller. It is sized well for my purposes even in the winter for charging a battery pack that will recharge a few flashlights, hand held radios, etc. Great product. I have 2 and am giving one to my daughter.

Added: I gave both to my daughter with the necessary cables and controllers to run the two in parallel or series. I added an inline meter so that she can see how well it's charging her lifepo4 battery pack. Now I'm looking at this as a third purchase for myself again. I know it's good stuff because I (a degreed electrical engineer) thoroughly tested it myself.