We've all been there--you finish setting up camp just before sundown and then turn on your headlamp to see it flicker its last bit of light as soon as you turn it on. Normally, you're out of luck if you didn't bring spare batteries; not so with the Black Diamond ReVolt Headlamp. It features batteries that are rechargeable via USB, so you can charge it through your car output, solar panel, or laptop. You can even toss in some regular batteries in a pinch. Dial in the right amount and type of light for the task at hand with proximity, distance, strobe, red night-vision, and dimmer settings. An adjustable headband allows for hands-free illumination, and a tilt function gets you the right angle for seeing what's coming at you. The three-level power meter takes the guesswork out of how much juice you have left.