I bought my Streamlight Nano flashlight on a whim (Amazon link). My other Streamlight flashlights have been great (except for the Stylus, kinda flaky). One penlight went through the washer with no ill effects, and my big “cop flashlight” continues to be impressive.
The Streamlight Nano is $7, 10 grams, and more weather resistant you’d expect in an ultralight flashlight. Plus, it has a really nice clip, which is good, because you’d lose it without that.
You turn it on by screwing the front down until it makes contact. This is the single fault with this flashlight — there isn’t enough resistance as you turn it on and off. The light can turn on in your pack and run down the batteries, or more annoying, unscrew and scatter four tiny batteries amongst your gear.
I fixed this by wrapping quarter-inch teflon plumbing tape on the threads to increase the resistance. This works great, and probably increases the water resistance, too.
There is one other problem, replacement batteries cost almost as much as a new flashlight. More, if you don’t shop around. But it is an LED flashlight, so they last a long time.
Mine is black, but they come in other colors, even pink. They are small enough to be a zipper pull, if you like that. So get a few, distribute them as Christmas stockings, party favors, rewards for the patrol with the lightest packs, whatever. It is a pretty fun little light.