1. One AAA battery (lithium)
2. REAL EASY TO CHANGE BATTERY. I like the ability to replace the battery in the dark. No tools needed.
3. Three or four brightness settings.
4. Can use as headlamp or regular flashlight. If it’s just a flashlight that can clip on your hat bill, that’s great.
5. Waterproof.
6. I’m probably a loaner on this but I like a strobe mode. That’s my most used mode. That’s the mode I use every day on my bike during daylight hours. I use the regular mode during backpacking.
7. Maintain constant brightness as battery is dying (regulated).

-Barry
-The mountains were made for Tevas