Thanks so much, I might as well try it. 
lucydogā¦
Thank you for posting this clarification.
Itās just hard to justify my reply when itās gone.
Yeah, it appears that the e/switch can not support the 10440 battery.
The Tool is a great light and I carry one in two of my outdoor grab hoodies.
I got my e-switch version today and was initially putoff by the UI. ā5 clicks to high??? Awe, h*ll no!ā Yet itās the one Iāve reached for throughout the day because it is one-handed and quick. I like it a lot, and I expect to like the reverse-click version even more.
Iām sorry for derailing this post, didnāt meant to.
Carry-onā¦.
good catch!
heres the feature/bug skinny
the eSwitch Tools on 10440 are high mode only until the battery drops to 3.8volts
massdrop aluminum tool is eSwitch, so 10440 feature/bug applies
there is also an aluminum Tool w Nichia and Mechanical switch, it does work with 10440, but bear in mind there is no overdischarge protection built into the light
same for Maratacā¦ no OD protection, and unsanctioned to use 10440, but people doā¦
Im a LiIon newbie, hung up on using protection in case I fall asleep with the light on
Hmmmm, now Iāll be researching whether my k18 has a protected circuit. As far as Li-Ion, the IMRās are fairly safe - and you can always use a protected battery (if it fits). I use 18650ās, donāt so much see the appeal of the 10440ās over the longer running lithium primaries, except for the pocket rocket WOW factor. I prefer the CR123 size for more power in a small package. Years ago I used a mechanical ecig that took 10440ās, lasted about 3 hours between charges!
In case anyone cares, and since this thread is all over the place anyway 
the 2017 version of the k18 does have OD protection:
http://www.ultratac.com/faq-items/does-the-k18-have-over-discharge-protection-for-10440-batteries/
so this is the rev. 4 model?
I do not know the Rev Number, there are no markings on the packaging to indicate Rev Number. But if I had to guess, I would say yes.
What makes you ask?
Maybe contact Countycomm to ask what Rev they were selling in December 2017, and share what you learn.
sorry to tell you, but i canāt remember why i asked, now. i also donāt remember what i had for breakfast, and itās currently lunchtime
lol
I think you wanted to figure out if it is Rev4 (it probably IS), because you assume, as I do, that they started using N219c in Rev5, and like me, you know the N219b is better, less green.
and, Yes,
I remember you want to buy my Maratac 
dont forget to send the money
ā¦itās starting to come back to me
iāve got about 10 of them now, and i think thatās being conservative. 4 copper, 4 titanium, 4 black aluminum, and that doesnāt include the worms
sooooo are those Rev 4?
and Got Nichia?
i know 2 have nichia andā¦ooohhh, pretty butterflyā¦
where was i?
better yet, who am i?
Now I do not know whether I was then a man dreaming I was a butterfly, or whether I am now a butterfly, dreaming I am a man
ā and/or:
Which side of the aquarium glass am I on ?
How many sides are thereā¦
A man went to sleep and had a dream he was a Copper Maratac, when he woke up he did not know if he was a Copper Maratac dreaming he was a man, or a man selling a Copper Maratac.
A man named jon went to sleep and had a dream and was blinking his eyes real fast and didnāt know if he had PWM or not
Then PWMWarrior awoke with a start and Shouted out in High CRI
NO! None of my Maratacs have PWM!
and a great battle ensued, in which the maiden was saved, and PWMWarrior lived happily ever after.
bump before withdrawing this sale
ok, withdrawn