If you're looking for a dependable, powerful flashlight, and you don't want to read a 20-page owner's manual in order to operate it, the E21 R4 LED Flashlight from Fenix is probably what you have in mind. The CREE LED throws out a high-intensity 170-lumen beam using just 2x AA batteries, with a second mode that delivers 54 lumens. The E21 is waterproof to 6.5', and impact resistant up to a 3.28' fall. It's constructed from aircraft-grade aluminum with an anti-abrasive Type III sulfuric acid hardcoat anodized finish. A high efficiency circuit maintains constant brightness in the beam.
At the maximum 170-lumen output, the runtime is 2.25 hours. At the lower 54-lumen output, output is 11 hours. Plus, there's a momentary-on function. If you happen to put your batteries in the wrong way, built-in protection prevents any damage to the circuit. That's it--a simple, highly efficient and powerful small flashlight that's easy to operate.
Second mode produces 54 lumens, with 11-hour runtime