No matter how long you charge your iPhone before leaving for the day, it seems to always die right when you need it – but this fantastic case will make sure that you never have to hunt wildly for an outlet ever again. The Gridcase Reactor is just a prototype at this stage, but it has the potential to be the case that everyone has on their iPhone 5 in the future.

The Reactor looks a lot like a regular iPhone 5 case, but it hides a cool little secret. On its back is a pop-up crank that you can use to give your smartphone a little power boost when it’s needed. You can crank it briefly for a small power boost or keep going until the battery is fully charged. Since arm power doesn’t generate a ton of energy, you’ll probably be cranking for a very long time…but if you absolutely have to charge your phone, all of that work might be worth it.

Although the idea is a pretty cool one, there are some obvious drawbacks. The case will make your iPhone significantly larger and heavier, and cranking a hand crank in public is something that most iPhone users won’t be super-thrilled about. But if your iPhone is your life and you don’t want to go even a second without it, the Gridcase Reactor might be the perfect solution.