Solar panels are getting small and thin enough to tote around in a pocket, said Bryan Lufkin at Gizmodo​. Solar Paper is a solar charger for smart devices developed by Chicago-based startup Yolk. Each 7.5-by-3.5-inch panel is, true to its name, "paper thin," and it weighs just 4.5 ounces.

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A single panel can generate about 2.5 watts of electricity, and "you can connect more panels with magnets for more power." In sunny weather, two joined panels "can fully juice an iPhone 6 in about two and a half hours." The charger connects to any device with a USB port; four panels in the sun will fully charge an iPad Air 2 in four hours. Yolk is currently taking pre-orders on Kickstarter ($89 will get you two panels) and hopes to ship the first chargers in September.