I normally buy my stuff from AliExpress, but I’ll see which one suits me best!
Although I am not much of AAA lights, these caught my attention, so I hope this is a good bet 
Thanks for your information and work on all!
And also for the clarification on the Lithium primaries batteries :+1:
One more thing:
Please note that the 4.000K version is really limited at this time. I'm not talking about hundreds of lights but more likely dozens of lights being available in the beginning. Originally, Wurkkos only wanted to sell the 6.500K 70CRI version but I asked them to also offer a less coldwhite HighCRI version to BLFers and TLFers. Eventually, they agreed to this request. Please regard it as a "test run" to see how it will sell. If the demand for 4.000K will keep on remaining high enough, chances are very good they will offer more of the 4.000K 95CRI version.
To any manufacturer making 1xAAA lights…
PLEASE INCLUDE A KEYCHAIN MOUNTING LOCATION
I cannot wrap my head around why lights like this WK01, Olight i3T and the Lumintop IYP07 would lack that simple feature which just seems like such an obvious inclusion for any light this small.
2 X AAA version is an exact replica of the sofirn SF02 body which is not a bad thing as I really like my SF02.
yeah simliar like SF02 and update with Constant current circuit and the touch feeling of the tail cap as well as a bit more output 
Not a real issue at all but just a minor, cosmetical imperfection: The CNC machining or post processing of the head units might deserve a closer look as I found some small nicks on my two samples, see pictures below. Again, nothing serious at all as this can also be found on Sofirn’s C01(S/R) lights, too. Moreover, the clip is slightly warped to one side, not being exactly in parallel to the tube - again, just a cosmetical imperfection for those being too nitpicking as me. After all, it will have no impact on the functionality of these nice lights. 
Apart from this, both lights are well designed and assembled.
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Thank you Lux-Perpetua sharing so many nice photos and details.
we found this minor cosmetical imperfection too , and talked to the factory they said it is difficult to avoid, maybe many people will have such complaints, I am thinking about how to help avoid this problem in the next batch,
The groupbuy is now active for European customers who want to order from Amazon DE, see updated OP.
The stock in Amazon's warehouses in Japan and the United States is yet to be released. I will update new codes as soon as stock becomes available.
Can the pill be taken out for en emitter swap?
The groupbuy is now active for AliExpress and Amazon JP, too.
According to Wurkkos the head is not glued, so it should be possible to dismantle the light.
WK01 looks nice
Absolutely. The new brown color looks very appealing. WK01 is a great alternative or addition to Sofirn's C01S. Using a constant current circuit was a very wise decision, too. Definitely a keeper, IMHO! :-)
Thanks! Looking forward to WK01 4000K in brown.
WK01 is now available on Amazon.com, see OP.
WK02 is now also available on Amazon.com, see OP.
Ordered WK02, hope the switch is better than the a02.
Update:
New codes for WK01 / WK02 on Amazon US and Amazon DE.
thanks for update the code
Update:
New codes for WK01 / WK02 on Amazon US, see updated OP.
Wurkkos WK01 SST20 4000K AAA forward clicky with Low, Medium and High modes.
WK01 SST20 4000K arrived today! I ordered it from the Sofirn Official store on AE.
I like the WK01 more than my i3T because of the 4000K tint and smaller size.
Are the drivers for WK01 and WK02 different?
Gonna say yes drivers are different,
Got the WK01 and tried to put the head on a Sofirn PF04, Thorfire PF04 and will not work, head is shorter, threads different depth.
I know people will say “just make a contact ring” but that would not be a good idea as I did put a LifePo 10440 in the WK01 and the modes just do not change and it really did not get much brighter so higher voltage is probably going to kill the driver with no gain, no upside.
Flashlight really works well at the recommended voltage though and the tint is awesome!
Could probably get away with primary lithium AAA which is usually around 1.75-1.80 volts and may see some increase in output.
Do wish it had mode memory, always starts on moon. Sometimes I need it to start on high like in daylight use under car hood etc.
HTH
Keith