Why just one? And if you loose/damage it??
Why do not you put a small 1xAAA with you?
Of course, a coupple of knives too (Sak/folder plus a straight one)
And don’t forget some pictures for all of us!!! 
Have a nice trip !
2 DOGS,
I plan on carrying a similar usb stick light, for use just as you described — with my miller. I plan on sealing it in clear packing tape to add some amount of water resistance. A backup light that only weighs a few grams seems worth it to me.
I am weary of the durability and water proofness of zoomies. I do like the throw in a lightweight package though.
I would pick a light that had some way of telling me the charge level of my batteries. Nothing like lithium batteries for dying suddenly. Always a good time when you are 50 feet underwater on a night dive. 
Are there significant differences between the pro and non pro versions? I don’t see any.
That is 1.8 pounds = about 800 grams + 1.3 pounds = about 600 grams, and hundreds of dollars. I thought he was going above ground!
People go way over board with this “two is one” business. A redundancy option is a good thing but it need not be of the same specification. For me a headlight is the main light and a single AA torch is the back up. The same goes for knives. A fixed blade is the main knife and a folder is the back up. When you have to carry your kit yourself you soon become sensitive to unnecessary weight.
I rarely use a light while backpacking/camping, but I know that there are nights that you need one, and also times like a tent blowing over on a stormy night, doing repairs on your equipment or your feet when there is little moonlight, or true desperate emergencies such as needing to treat an injury or find dry firewood or some gear in pitch dark, or even having to stay on the trail all night for some reason.
We lose flashlights, especially small ones, and on a solo hike I think two small but high quality lights is worth the weight, because when you are alone, light could be a matter of life and death in some scenarios
For me, my Fenix LD12, and my Fenix HL10 headlamp sound great, although as I got closer to the trip and weight became more and more an issue, I may want to trim that down to the HL10 and my Fenix LDO1.
I assume you carry a bandanna, well a little light like the LD12 or E01, or LD01, can fit perfectly in the knot of your headband, and at the correct headlamp angle.
The model of LD01 that I have is all the light one needs anyway, so it and the HL10 gives me pretty much everything I need
Another great light is the Photon Proton Pro, the option of using the red led might become preferred. Amazon.com
You could also consider the paklite 9volt light as a back up to your primary light (or as your primary). http://www.9voltlight.com/
Another back up light is Amazon.com
I agree.
I also find that insane!
+1 Lithium AA's are lighter than Alkaline. Outside the city in the real darkness a little light goes a long way.
lol… I like to bring bright lights when I venture in darkness… the question is, how long do you go for hiking that you can’t carry big light?., Fenix TK75 is one of the lightest “big” light, I wouldn’t like to get lost in the darkness while only having AA lights.
As matter of fact, heck I don’t remember when the last time I ever used AA lights anymore.
but yes… I might read the OP question wrong, OP want to know if you could only bring 1 light what would it be?
after giving some thought, I think I would bring the warsun A9 light, great light with great run time and can handle the abuse of being drop or rain.
EDIT: never mind my comments… OP think Lucky sun D80 and alike is too heavy, in that case I would just bring Nitecore HC50
Let me be more clear, since I do myself like from time to time to bring a BIG monster light for the fun of it. Cuz’ it’s damn fun sometimes and friend’s impressed comments are more than worth the bulk
What I think is valuable in night hiking and hiking in general:
- reduced bulk and weight for more fun, less fatigue, less opportunities for injuries = little, light and single or double cell powered fashlights
- night adapted vision (which is wise to preserve) = need for little lumen numbers
- short hike = li-ion rechargeable cells pack lotsa Wh per gram
- long hike / travel with uncertain access to grid = AA and AAA cells are more easily sourced about everywhere except flashaholics’ homes
- campcraft at night, working hands-free, walking on uncertain terrain, using hands to balance or grapplig, sharing places-maps-social activities with companions = HUGE advantages to floody lights and headlamps
Lighter also means less damage when dropped off, which in the outdoors is likely to happen and thus greater reliability that comes indirectly is appreciated.
In general I would advise to go for warmer tints or high cri floody headlamps, plus an handheld semi-throwy light to see stuff in the distance (plan a route on the dark, spotting trails and obstacles, look for the slender man before it gets too much near).
Sharing same battery type between flashlights and other devices gives more flexibility and safety in case of need.
Calculate needed runtime, double that, bring spare batteries accordingly.
I would carry 2 LED flashlights that use the same type of battery, and are adaptable to other battery chemistries, one for throw and one for flood, both water proof.
Would be great if there were a high quality solar or crank to charge flashlight, so far haven’t seen one, are the solar battery chargers any good?
So I decided to purchase a armytek wizard v2 NW (non pro version). It was $60 after coupon code. I couldn’t justify the extra $25 for the strobe and tail magnet of the pro. The next item I need is a lightweight 18650 light that has a little bit of throw. The P12 looks like it may fit the bill.
Alex GT-
As far as I know the weight of a solar charger is rarely worth it. Your much better off carrying a few spare batteries.
So one more update. I finished a section hike of the AT. I took a wizard pro neutral. I now have a new respect for shaving off ounces. Therefore, from now on, I will stick with just a headlamp and a very lightweight backup. The wizard was great, but I still find myself wanting more throw. But I have to admit, the wizard is the most useful light I own, on or off trail and is definitely good enough.
What about an AAA 5mm LED light for a backup? Stoked with a lithium primary, these things can be a great, long running backup, and they are light lights… Fenix E01, Klarus Mi02, there is a thread HERE
I would bring my K40M even with the weight! I JUST LOVE THAT LIGHT
I would now bring my 14500 LED Lenser P5.2 modified with a two group Nanjg 105c driver, and a 10440 SS-5039 with a BLF Tiny 10 driver. Maybe a spare lithium ion cell for each. I might bring a CNQ Host based 18650 light instead of the 14500 if I wasn’t too worried about weight.
The hard part of the question is just one light ...if it has to be one light than a headlamp is probably a really good idea . Depending on if it's a climb or more of a hike as to whether weight is a bigger issue .On just a leisurely hike a 18650 light with some throw probably makes more sense. a p-60 or something like the x6 eagle eye ..that said a straight tube light like a xaiozhi or a s2 convoy work for about 95% of everything I ever need in a flashlight ...runtime and color rendering are very important to me when in the woods . i used my Hd2010 to tromp thru the woods and it was horrible and just drove home my eternal hatred for bad tints /low cri .
Easy answer is two lights a headlamp and something with some throw....both with good cri