Comments on the thread:

1) I mentioned this light as being interesting for tiny PSK's, e.g. Altoids tin or the even smaller mini-Altoids tin. Every cubic millimeter counts in a kitlike that. For normal keychain use, a normal Photon-sized light makes more sense. It lasts longer and is easier to operate.

2) Brightness/longevity/throw: with new batteries this light is about as bright (i.e. puts out about the same total amount of light) as a Photon. However, the light is less focused (bigger hot spot) which is better for close-up viewing (wideangle coverage) but there is considerably less throw. Longevity is also reduced a lot because of the smaller batteries. The LED Museum has a runtime test on a similar light and it was pretty feeble after about 1 hour, while a Photon-type 2016 light is good for 3-4 hours. Both types of lights are much brighter in the first few minutes than afterwards, though, so don't expect the very impressive initial brightness to last too long.