[LorenPechtel]

I have a headlamp for hiking with a slightly different take on this.

It will take 3x ordinary or rechargeable cells, or it will take it's Li-Ion pack that is the same size as the 3 cells side by side. Designed in from the start so there are no dangerous bits. Hiking headlamps are something where you do *not* want to be left with a dead battery!

[Zak]

A headlamp that can run on either AA or 14500 tends to be a better approach than this. Those proprietary batteries are usually pretty expensive compared to a 14500, and three AAAs as spares aren't nearly as convenient as one AA.

There are a handful of these on the market and they're not common in retail stores. I'm fond of the Skilhunt H150.