Several years back I reviewed this tiny zipper pull light: https://lemmy.world/post/2163520

I stuck one of them into a mesh pouch where I carry stuff like toothpaste, and more than a year ago (IDK exactly when) it turned on by accident. I left it on to see what would happen. It has stayed lit ever since, though by now the glow level is completely useless for illumination and barely viable as a locator. As someone in Bored Of The Rings said of the parody version of Gandalf's staff lighting up in Khazad-dûm, it's about half as bright as a dead firefly. But I can report that with some dark adaptation, I can see it from 5+ feet away (and probably further) in a darkened room. I finally just got around to replacing the battery with one of a pack that I got on ebay (link in the original post).

I also notice that the light itself is discontinued now, oh well. It does seem to me that it turns on by accident too easily. I might stick down the on-off flange with a bit of tape to prevent this.

The original vendor blurb just said 24 hours of light so I might use up a battery to test that, or maybe for a week. It might be ok as a short term alternative to a tritium marker for that much time. I would say in its current state it's way dimmer than a tritium marker whose tritium isn't nearly depleted.

It also seems to me that at under 3 grams, this is maybe the most extreme ultralight headlamp out there, if you stick it to your forehead with a piece of tape. It DOES put out enough light to be useful in that setup, for limited notions of "useful". You can navigate a dark room without bumping into stuff, you can see near-distances enough to change the battery in your main light without having to fumble around by feel, and so on.

Since the light is just a direct drive SMT led and a CR927 cell, it could be that something similar with a CR1616 and a resistor (or go big and use a CR2032) could be used as an H3 substitute that would last for months.

It's too bad they discontinued it. I have several of those that I have used on my dogs' collars at night and they've been perfect for that.

I think they on/off function is stiff enough not to be activated by accident under most circumstances, but a slide switch would be better.

The one I have that turned on by accident has gotten quite loose and turns on too easily. The plastic might be worn from too much twiddling. I wonder if I can fix it somehow, like by adding a piece of tape around the rotating part. I have another one someplace but would would have to find it to compare them.

They do make a bigger one for dog collars or you could do something similar with a Photon-style keychain flashlight. The Ziplit's tiny size is nice though.