Dubai Design Week, a festival that showcases an extensive array of work by designers from 26 countries, kicked off October 24.

One exhibition, called the Global Grad Show, showcases pieces created by students at the world’s leading design schools. Since it launched in 2015, the show has become the largest exhibition of student-made design work in the world. This year, students from 50 different universities, representing 30 countries across six continents, traveled to Dubai to exhibit 135 projects.

Kyuho Song and Boa Oh, graduate students from the Samsung Art and Design Institute in Seoul, are showcasing their clever prototype for a solar-powered socket. One side has solar panels, while the other has holes where you insert a two-prong plug.

You just stick the suction cup to a window when it’s sunny outside, and the mini-solar panels transfer power to the socket’s internal battery.

It takes five to eight hours to fully charge the socket, which can offer up to 10 hours of power, Song tells Business Insider.

Right now, the socket can store about 1,000 mAh (amp-hours, a unit of charge), which is enough to keep a 60-watt light bulb lit for about 20 hours. It’s not quite enough to fully charge a dead iPhone, however, since the iPhone 5 features a 1,440 mAh-capacity battery, and the iPhone 6 Plus battery needs 2,915 mAh.

In the next iteration, Song and Oh hope to increase the device’s battery storage and charge time. The solar socket is still just a working prototype, and the team doesn’t have any plans to sell it yet.

If the duo is able to amp up its efficiency, the device would come in handy when your phone is dead and an outlet is nowhere in sight. Song imagines the socket could be especially useful in places without electricity, like an airplane, boat, or the outdoors.

In addition to the convenience, of course, it would offer a more sustainable (and cheap) way to generate electricity.