This article originally appeared on PureWow.com.
There’s nothing quite like escaping to the woods for the weekend, until your phone dies and the world is without any Instagrams of your adorable rustic getup (nice job pulling off suede in the great outdoors).
That’s where FlameStower comes in. The small, portable charger ($100) uses the heat from a campfire to juice up your devices. For real.
The size and shape of a flat cheese grater, FlameStower clocks in at only 10 ounces (that’s like two iPhones) and fits easily into the side or front pocket of your backpack.
Here’s how it works: FlameStower unfolds into a stand that has a silicone reservoir for water and a metal blade that you stick into fire, and uses some pretty cool basic science to keep your electronics powered up. Connect the USB port to your device (phone, GoPro, Fitbit), fill the water cup halfway and stick the blade into the flames. (This sounds way more MacGyver than it is, trust us.)
The heat from the campfire, or even from the flame of a portable stove, converts into a thermoelectric circuit. Translation: The temperature difference between the fire and the water creates electric power. Twenty minutes of charging buys you 40 minutes of picture snapping or GPS tracking.
Powering up your phone while toasting marshmallows and making s’mores--we can’t think of a more efficient use of time.