Since i've upgraded my gravel bike to the electronic wheeltop groupset i no longer need my GRX 12 speed rear derailleur.

Max biggest cog: 51 teeth

I've bought it in january and have the original invoice. I've ridden it for less than 100 km so it's pretty much new. I can include a shift cable if you like.

If you are interested feel free to message me. I'm looking for around 60€.

I am located in germany.

Speaking of know-how, these are the words of CEO Colnago in an interview: "We have the V Series which, like almost all racing bikes made in the world, comes from Asian countries (China and Taiwan). And not for price reasons but because they have developed notable skills on carbon there".

Well I agree with Serge_K
Things i have noticed in the last 4 years have taken a massive leap, and yes knowhow is spread.
Joe Whittingham also say this in his YT China Cycling channel or interviews he has had with other you tubers.
People move around gain knowledge an pass knowledge on so everything keeps getting better and the Chinese have caught on and are developing there own brands as that is where the $$$ is
Xiamen obviously is where at is at for the industry
   
                                                       Xiamen                                Shenzhen/Guangdong                            
Specialization in Bike Frames   ✅ Yes, major hub                     ❌ Not primary                            
Carbon Fiber Application             Mostly bicycles   & Wheels             More tech & drones                  
Production Costs                 Lower than Shenzhen                   Higher labour & land costs        
Presence of Big Brands          Many OEMs/ODMs                             Few frame makers   

I'm very very interested to see this frame when I receive and build it against the real thing, it may possibly get to a point where I stop buying the western brands
Same is for watches I have well a pricey watch and now the $1000 copies are near on indistinguishable and need experts to make assessments to there authenticity, as people are getting caught out buying as genuine which may just happen with the bikes.
I buy a real one  and a copy and get it same colour decals etc and dont register real frame  and sell it with warranty there you go!     
And before anyone says anything no I am not planning to do this I do have a moral compass!     
   

Photos of the build! As I mentioned previously, I can't ride the bike right now due to major fires in my area, so I can't comment on ride quality until things clear up. I've included close-ups of the UD glossy raw finish. In-person it looks like black marbling, similar to a bowling ball with similar finish! Also I pre-applied clear protection decals to certain areas of the frame. Some of the straight lines in the finish are from the protection decaling.

That stem/handlebar combo looks slick to be a non-integrated handlebar. I assume it is Uno stem, but what handlebar is that? And another thing - did the top cover for the headset come with the frame kit?

Looks solid. Thank you for sharing! I'll bookmark it if I ever build a dedicated trainer setup.

On a sidenote: that dashboard gives me anxiety 
(I know it's just to showcase what metrics you can display and probably nobody will ride it like that)

It's fully customizable so i'd probably delete everything apart from the virtual shifting. UI wise it's certainly not the nicest app but as long as it gets the job done i don't mind.

Looks solid. Thank you for sharing! I'll bookmark it if I ever build a dedicated trainer setup.

On a sidenote: that dashboard gives me anxiety 
(I know it's just to showcase what metrics you can display and probably nobody will ride it like that)