Old thread, but the Flare is now discontinued and hard to find, and meanwhile there's a super cheap ($1.97!) 2x2032 headlamp now at Walmart:

https://www.walmart.com/ip/Ozark-Trail-S...Teal/1832307583

I got a few of them and they work and they're bright enough for most close range stuff. They're plastic and the quality isn't great, but the main point of unreliability I see is the mounting bracket, which could wear out with not all that much use. Weight is 27g including light, headband with mounting bracket, and batteries.

There's a new Lumintop L3 that looks interesting, 11.7g which I think must not include the battery or headband. Uses 1AAA so you could put in a lithium version:

https://lumintoplighting.com/products/lu...-waterproof-362

It's currently out of stock on their store but maybe more will show up.

Someone mentioned the Manker E02. I have it and am not crazy about it. It's too bulky and the UI is too weird. It's around 23g for just the light, and the headband is full sized and kind of heavy too, though you could make a smaller and lighter one.

Best is probably this: https://www.nitecore.com/product/ha11

Uses one AA, 38g weight including headband but not battery, so add another 15g for a lithium L91 AA. It can alternatively take 14500 rechargeable lithium ion for non-emergency use. By changing the headband to a shock cord (many ultralight hikers do this), you can probably save 5g or so. Here's a detailed review of an earlier version, by a flashlight nerd:

http://parametrek.com/blog/ha11.html