Doug's e-PICO light is the first light I've ever had on my keychain that I can be confident won't accidentally be turned on and burn up the batteries so that it's dead when I need it someday. That was the most important consideration for me. And the e-PICO light on my dog-walking lanyard (with house key) is so tiny that I don't even notice it. That was the other most important consideration, for me.

I'm surprised it only costs $12.

Since I always have a house key with me when I'm out of the house, thanks to Doug's e-PICO I'm now 100% certain in an emergency to have a light that's extremely likely to function. And I'll have 15 hours or so light available.

That should get me out of an elevator or any other likely urban blackout scenario. That's why I'm so delighted with the e-PICO.

That said, I'm interested in whether the lithium battery mentioned would be fine with the e-PICO. Longer shelf-life is nice.

I have so many flashlights and headlamps in my home and car and at least two LEDs in my backpack when hiking that I don't have to be totally reliant on any of them.

None of those would be comfortable on a lanyard.

{my other favorite emergency light is the Petzl e+lite headlamp with lithium wafer battery]