Panasonic 2CR5 6V Lithium Battery

I've been using these in my older film camera and they last through several rolls without any drop in flash performance. The lithium chemistry gives it a much longer shelf life than the alkalines I tried before.

Popped this into my Canon and it’s been running strong for three full days of heavy flash use. No drop in power even in freezing weather during a dawn shoot.

Went through a full weekend of shooting—hundreds of frames—and the camera never blinked once. The 6-volt output feels rock solid even in cold weather, which is exactly what I needed for outdoor work.