The Sandberg Outdoor Solar Powerbank 10000 lets you charge your smartphone up to 4 times. And yet it is still super compact and does not add much extra weight to your backpack. The power bank is equipped with an efficient US-made solar panel, which generates enough power for an extra charge of your smartphone on a sunny day. The power bank is firmly wrapped in an IP66 shell that is safe in all kinds of weather, and can withstand being lost in the snow, sitting in the back of your backpack while hiking through a river, or being dropped in the desert sand.