I also have to have a shout for Yeenon.
Too often Chinese adapters are talked about in a condescending way: “Not bad and they are cheap” (so if they are not “perfect” then they are at least affordable.
Some will pay “eye watering” prices for adapters made in Germany or Japan simply because they are “accurate”. But as a general rule I have found Chinese made adapters cheap, accurate, and well made. Of course I have had some glaring exceptions that have proven the rule. Nevertheless I have saved a lot of money by buying Chinese made.
But Yeenon swim against the tide. They were the only maker of DKL adapters years ago and as I had some Schneider Kreuznach DKL lenses made for Kodak Retina then I paid the price hurdle (almost to high to jump over) and was rewarded by the most exquisitely made lens adapters I have ever seen. Yeenon had replicated the build of the female part of the DKL mount and the aperture mechnism faithfully and precisely right down to the materials used. This was a M42 mount adpation but they make others. When mounted the adapter is such a faithful replication that it is impossible to tell that the lens was not made as an OEM M42 lens. Even the little red “trick” moving dof indicators are there and adjust automatically to suit the maximum aperture of the lens.
I have called Yeenon adapters “jewel like” and I have no reason to resile from that.
...
In the end I suggest that Yeenon must get the award for the best quality adapters persently made. Not only are they impeccably precise but the complexity of construction and materials used are utterly beyond reproach.
So we have to re-adjust our streotypes and have to start realising that Chinese made can be very well made indeed as Metabones products will also attest. Furthermore if we can find the very best we might have to pay top of the market prices for them.