The Fenix E12 V3 proves a single AA battery can still deliver a genuinely capable everyday carry flashlight. It puts out 200 lumens and reaches 256 feet, with a memory function that remembers your last-used setting so you're never stuck relearning the interface. A flat tail lets it stand upright for hands-free area lighting, a built-in magnet sticks it to any metal surface, and the two-way body clip rides just as well on a pocket, belt, backpack strap, or cap brim.
Stretch the battery to 100 hours on its lowest setting when you need to make a single AA last. Rated IP68 for full submersion up to 2 meters and impact-resistant to 1 meter, the E12 V3 is small enough to forget you're carrying and tough enough to matter when you need it.