Thanks! I went to the Sofirm site and found the IF25A, so am looking into it now, too!
Don't laugh, but there is a point to what I am seeking. I am blessed to have a large backyard. Large enough that I have to sometimes search for my dogs at night, after letting them out. I'm looking for 1k lumens or so, such that I can light up 1/2 to 3/4 of my yard enough to see where they are/what they are doing. But because I am sometimes wrangling them, a small light I can clip to my collar is most desireable (once I find them, LOL).
Thank you for the explanation!
one man’s small is another man’s large…
I suggest you develop some data regarding the weight of each light you consider, as a basis for comparison.
.
OlightS1R compare and contrast to Sofirn SC21
Olight LED is not HIGH CRI
to me, High CRI is a required feature, and is the reason I no longer own any Olights.
Sofirn offers High CRI, Olight does not
Olight UI is not Anduril
I like the Olight UI, but not their LEDs
Anduril UI is MUCH more complicated, and requires a LOT more clicking to access all the extra features…
Anduril is a very high output capable UI. People have been hurt when the light accidentally turns on in their pocket. Prudence dictates locking out lights that run Anduril. Locking out requires 4 clicks to lock, and 4 clicks to unlock.
to me that is a ridiculous amount of clicking, and one of the main reasons I do not own any Anduril lights myself
otoh, if Anduril UI interests you, the SC21 is the smallest and lightest Anduril light presently available
to be fair, Anduril is extremely versatile and capable, and can be set up to be as simple or as complex as you like…
warning, if you slide down the Anduril Slope, you will soon be buying an Emissar D4V2 with aux lights… and more… you have been warned 
welcome to our support group… LOL
Based on your response, I went over to the general area and spelled out "small". Thank you for your help!
Will
I think the SC21 is not anduril.
I dont own the light, and you might be right…
the word Anduril does not appear… so, who knows?
it does say:
Group 1: Stepped mode group
Group 2: Ramping group
SC21 does not use Andúril but more or less a quite similar UI as SP35. An excerpt from the manual...
thank you
similar 4 click lock and unlock as Anduril
similar stepped and ramping modes as Anduril
I dont know all the differences between Narsil, Bistro, Anduril etc
imo ramping is a useful UI
as is the option to use stepped modes instead
so afaict, this is the smallerst light available today, with a ramping UI…
Is there an AA/Eneloop version of a light with a ramping UI?
(that does not require LiIon?)
After a long wait mine is on its way.
Here’s a pretty decent video review. Hate to say it, but it might push me over the edge…
I have one and it’s awesome for features, lumens and size. I would only step down to an AA or AAA if I wanted to go smaller than the SP31 Pro 18350. And now I’m locked into the 31 Pro, Anduril as well.
That video does make it look tempting.
One question I have, is that can it go directly from moonlight to ramping by continuing by holding the button in moolight, like the SC31 Pro can?
I like the UI on the SC31 Pro.
glad you found an 18350 Anduril light you enjoy
can you please tell us how much it weighs?
My favorite 18350 light weighs twice as much as an SC21
both is best 
and
size matters… lol
aaa, 16340, 18350
Right at 80.0g inc. battery and clip, or 2.82 oz.
Are those slots on either side of the switch for trit capsules?
thanks
so SC21, 55 grams
SC31 short, 80 grams, (45% heavier)
.
Hmm, so it is egg-weight.
What is also nice about the sc11 over the short tube Sp31-pro is that it has a pocket clip. You need to source one from Mars to fit the short tube sp31-p from another make/model.
I used the clip from the SC31 Pro that the head and tail cap came from. All you really do is replace the battery tube for $1.49 (Sofirn Store) and buy an 18350 battery. The short tube only has one clip groove, so to change from forward to backward facing, you need to swap the tube 180 degrees. You had to start with a full sized SC31 Pro version anyway since I do not believe they sell an 18350 as a complete light. It is great clipped above or below the bill on a baseball cap. Not enough weight to matter.
It makes a nice, cheap upgrade to the SC31 Pro and you can always go back to the 18650 configuration if you choose.
I’m still thinking to get this or not. As I already have sc31pro which is as good as an 18650 light with lesser runtimes.
I would immediately get one if it was dual 14500 and AA though. with usb C charging for 14500 and option to use AA when you can’t charge. That’s the best option for EDC imo.