AAA, you must carry spares.
I am one Who Must carry a Flashlight, or Flashlight(s) . . . I have worked Nights most of my life.
I have lived Off Grid, as well. And required Light out doors.
For my Work, I carried AA Mini Mags for a decade, and did the LED upgrade, as soon as they came out.
For the last three years, I have retired the Weight of AA's, for AAA Batteries, and Expensive Flashlight brands.
but One MUST carry back up AAA's, and these tiny Tenergy Battery cases are Perfect for that purpose.
I also STORE my spares in Energy cases, it just makes sense,
ProsSmall, Light weight DURABLE.
ConsNone. and there really is no Product to replace it.