It’s a portable solar charger, roughly the size of a hockey puck, which uses a suction cup to attach to any available window. It also has a standard electrical plug — though right now it’s only the European standard — so once it’s done charging you can plug an appliance into it right there on the window, or carry it around as a portable electrical outlet.
Obviously, the device would be most useful on a trip, in a plane, a bus, a car, or outdoors — circumstances in which an outlet might be hard to come by.
Besides the lack of an American outlet version, the Window Socket also has a few weaknesses. It takes five to eight hours to charge completely, which is a serious chunk of time, especially in travel situations — though it lasts ten hours after that. Furthermore, as Mother Nature Network notes, the design currently doesn’t deliver enough power for anything other than small electrical devices:
As pointed out by more than a few commenters — the device’s initial appearance over at Yanko Design impressively garnered more than 300 comments — the big drawback here aside from the slow charge time is that the Window Socket’s battery is currently at 1000mAh which isn’t enough juice to really power anything save for a smartphone or other low-voltage mobile gadget.
Though again, if travel situations are what’s primarily under discussion here, than enough juice for your smartphone may be all you need. And presumably, further improvements in technology will bring down the charge time and boost the power delivery.
Other developments in the world of portable solar power include roll-up panels for the military, and a new ultra-thin solar panel design that may be able to fit directly on smartphones and other such devices.