Is there no way to tell by looking?
Yes there is if you know what to look for. I'll use a few examples:
The left board type I bought once, it is not DTP and can be seen in the substrate. The thermal pad seems like a track which is floating over a dielectric layer, pretty much like both anode and cathode tracks. The right board stinks too, imho.
The above are DTP or thermoelectric separated boards (bought and have both). Notice the outlines around the thermal pads, they're sort of window shaped, profiled strictly around the thermal pad and the contact points. Being DTP it does not need to be any bigger since it is not a track whose surface matters like in the previous examples, i.e. it is the whole board core.
Source: https://www.aliexpress.com/item/32727123202.html
I bought fairly priced ∅20mm copper DTP boards once from here: https://www.aliexpress.com/item/32894842920.html
Taking a look,
the window around the thermal pad can be spotted.
Much appreciated.
Just as I thought when I compared to KD’s mcpcb. Confirms that mine aren’t dtp for the Osram red, I’ll reflow one to the KD board. It’ll be great if I can drive them harder.
They’re currently on 3535 so using 3030 may improve too
I was going to buy Convoy’s newly added 3030 boards but can’t tell by photo if really dtp?
I really doubt Simon has any interest in run-of-the-mill boards. Had to look: 20mm DTP copper board for 3030 LED / for osram KW...
Pretty explicit. 
What he said, This method is excellent.
The led4power dtps are nice quality! a good flat fit to the host with some grizzly kryonaut and you’re pretty well sorted.
I ordered from here last week but until they arrive I will remain skeptical
We have waited two years for this LED to finally become available! Supposedly the ultimate thrower LED.
Interestingly, the SBT-90.2 which became available in the meantime is a better fit for many larger lights.
:partying_face: I hope it will not be to hungry…
That “HX” from AE (YinDing) seems off. What’s with the exposed gray portion next to the die? Also, their other white flat listings have unusual markings on the surrounding white areas of the package.
I’m using their red flats and they’re legit
I would guess preliminary version of LED (is why it looks different)
I got here 2 flashlights with supposedly Osram NM1 LEDs
Both have some letter markings on top of the LED, but one of them also has a grey bar on the side (while the other does not).
Is there any difference?
Why do you think they call it LED lottery? You are supposed to scratch it off and see if you win!
/s
no idea
As contactr mentioned earlier. I’m presuming this is a pre-production or engineering sample type marking…
Another 2 flashlights with Osram, one has the gray bar, the other doesn’t.
Any specs?
The right one seems to be the CULPM1;which is the higher current version of CSLPM1.TG. There aren’t too many manufacturers around which use them
They look the same size to me. isn’t the CULPM1 the 2mm version?
Both flashlights are the same model: Manta Ray S21 with Osram NM1 LED (supposedly) - one has a gray bar, the other does not. The Manta Ray S21 uses a 2.8Amp (7135x8) driver, but the UI is sort of different (it seems to be related in terms of configuration as the Convoy C8+ SST40 ‘ramping’ driver version).
In my other set of Osram NM1 photos, one is a Wainlight C8S-G with Osram NM1 LED (no gray bar), the other is a Boruit C8 with Osram NM1 LED (but has a gray bar). The Boruit C8 and the Wainlight C8S-G look very similar (they use the same flashlight host as the Convoy C8+, but place an Osram NM1 LED and both seem to use a driver that is similar to Convoy’s 5/3-mode group driver (also 7135x8 or 2.8Amps).
you’re correct
i was thinking about this one