Ah, thanks.
Very good of you to find and translate this, however
I think something is lost in translation or perhaps just wrong.
If you look at this picture and consider that the LED is 5mm,
there is no way the star can be 21mm. It appears to be 16mm.
Looks like the LED will fit on the star 3 times across with 1mm left over (16mm),
definitely not 4 times with 1 mm left over (21mm).
I do believe after seeing this picture that the star is 16mm.
What do you think?
“16mm tube mount” must be referring to the star
It is more likely that the actual tube of the light is 21mm, but the star can’t be.
I think this picture pretty much confirms it is 16mm based on 5mm LED.
Has anyone seen this light in another store (BG, FT, etc.) ?
Oh, & welcome to BLF, NFRealBathrooms. 
Thanks. Yes, I’ve seen it on AliExpress
Yep, definitely 16mm. Thanks guys.
Sorry, my bad
Definitely NOT 20 mm, must be 16mm
Now, how easy is it to “transplant” this:
https://www.fasttech.com/products/1609/10003889/1425004
Genuine Cree emitter into this particular light?
Is it literally just a solder off, solder on type deal?
No, you have to add some thermal paste as well.
Yes, it is that easy
That’s why I generally don’t buy “complete” lights anymore except to use as hosts. I kinda count on replacing the driver and emitter…
Wellp, unless it comes with a nice emitter right out of the tin. Then there’s still the driver/UI… 
There be 2 main sizes for most flashlights. The 16mm round “star”, and the 20mm roughly hexagonal star.
You can (generally) use the 16 in a light that takes a 20, but not verse-vica. It may look funny, but it’ll work (’though with a little less of a path for heatsinking unless it’s got a nice beefy shelf).
There’s a little bit of slop even in a 20-on-20, because the LED itself may not be perfectly centered, and you don’t want the reflector/spacer pushing it aside (lead doesn’t “flow” over time”).
All bets are off, though, it you get a cheap-crap light that has a “hollow pill”, where the star only rests on a ledge around the edges. Those lights kinda suck anyway, so avoid them if at all possible.
So…
16 on 16, yes
20 on 20, yes
16 on 20, yes
20 on 16, no
Only on smaller lights (eg, “keychain” lights) will the “star” be smaller, eg, 12mm or so.
Do you have your heart set on that particular light?
If it has built-in recharging, chances are the driver won’t be standard. Ditto with a side-clicky. Can be done, but not recommended for n00bz.
Great starter lights for modding are the C8 (older type 1 with pill), and any WF-501 or WF-502. Those take
“pills” (pillars), which have the LED on one side and driver on the other. No grubbling around inside a head where you gotta fish wires through a small tunnel, etc.
My EDC is a ’501, and it’s a great little light. Got a bevy of replacement parts, so if you get sick of a SMO reflector, you can drop in an OP and compare, or switch back’n’forth as your moods dictate. Or buy extra pills, and make up a bunch, also easily replaceable. 1-mode or 3-mode, NW or WW, battery-killing luman-beast or long-runtime everyday light, white/red/UV/etc., you name it.
I won’t even mention my C8 army… 
Point thy browser at Fasttech, and goeth ye crazy.
If you don’t think you want to buy a tube of thermal grease (artic silver 5 or equivalent)
you can try to scrape it off of the old star and apply it to the new one. Your mileage may vary.
There may not actually be any on the light in stock form, many cheap lights have none.
Then just a matter of unsoldering the 2 wires, tinning the pads on the new star, and soldering the wires to the new star.
Ugh, I feel like I’m asking dumb questions. Is Fasttech credible? I saw it listed on the thread about sources for genuine Cree emmitters.
I’m not gonna mess with the driver at all, I just wanna put in a good emitter. Too difficult?
Fasttech will be fine for the emitter.
Definitely not too difficult. 2 wires. Unsolder resolder.
You will be happy with that tint you linked,
especially getting to see the before and after
and the satisfaction of modding your own flashlight.
Sounds good. I shoun’t have any issues with the pillar, as it will be a 16mm to 16mm transition.
You kidding? I ordered enough stuff from them I could open up Fasttech America™…
^ lol
I like the pill and reflector of this light, and how it screws together.
(I didn’t buy it though.)
Whoa, hey, NFRB…
If you’re planning on ordering the light in the screencapped ad for 12bux, I’d suggest looking at the Ultrafire D08. Apparently it’s also got internal usb recharging, and can take a 26650 or 18650 (with a sleeve). I’m probably going to order a couple just to dissect, and maybe mod, maybe use as-is.
I got a few similar-looking F13s, and the emitter is kinda nice right out of the tin, but I did a mod on it (driver and LED). UF seems to have some nice decent lights, so I suspect the D08 would be as nice as the F13.
See Ultrafire F13 mod if you don’t mind crappy pix.
Nice thing about the D08 is that at GB and FT, it’s only like 15¢ more, yet it’s a much better light. (Lookit the reviews for the one you want to order. Def some “quality issues”…)
Or if not the D08, go for the F13 for only a buk more. Nice simple workhorse.
Still say that for the best bang for the buk, a ’502 is king. And really easy to mod. And a damned nice-looking light. Doesn’t look like something cobbled together from spare plumbing parts. 5bux for a host, 8 for a complete light. Can’t beat that.