Excuse me I will have to be honest here.
Disclaimer: I printed with PETG so maybe another filament will have better result.
The cup is nice and the driver fits snug. with the screw on cover working flawlessly, so far so good.
On to the clips, I had to scale them a little bit on the width to have a good fit, otherwise it wouldn't enter. As of the "pins", I could not get a reliable fit, easily fixed with a bolt and nut, I recommend this if you want something more solid and safe.
And now the headband. The frigging headband... It took me hours to get the first layer to stick well because of the little pins in the elastic part. I guess we can say my printer wasn't well calibrated and I learned about PETG first layer adhesion (I ended up trying Kepton tape and spray glue) but it was still a challenge. Once I managed to get a good print, it was all stuck together. As I tryied to free the joints, it cracked and I lost most of them. Second print, better result ( I kept some pieces from the first headband as they are detachable) but I still had some cracks as I freed the joints. Even if it didn't crack, the joints go too far and they are the first part to move when I put the headphones, before the spring can actually bend. This results in an unequal and very low amount of force on the ears and a horrible sound quality.
In the end, even if I press the phones on my ear to hear the best possible quality it is pretty bad on the bass/side and too bright... I don't know what I expected. Well, in the drawer these go!
I guess the folding mechanism is neat and the pictures look good, but the design could be made so much stronger and less fiddly on the joints. For example it could call for simple nails or bolts as joint pins which assure a stirdy movement, also the lip that extends to stop the headband pieces from bending in the wrong direction is too short and is easily useless.
for reference, these are the driver I purchased: