You might also look for a 1/2" wide version of the glow-in-the-dark tape in your local hardware store. I found mine in the 'safety and childproofing' section. It was fairly inexpensive so I figured if it worked at all it would be worth it. I wrapped a single wrap around a couple of flashlights.

I was surprised to find that this cheap stuff was quite good. Exposed to a moderate amount of light they glowed quite strongly for a few hours and more dimly for most of a night.

The real benefit is that even slightly 'charged' by just incidental ambient light the single band of tape is more than good enough as a marker to find the flashlight dropped in pitch black while off.

I could see marking a few bits of vital gear that might be needed quickly, or dropped, in the dark.