The wheels are all mold matched in each tube. There will be a date on one of the wheels, mine showing 07212016. 4 wheels weigh about 10.40 grams, more or less. I believe that's less weight than previous China wheels.
Here's a big problem. I have a Concentricity gage from Derby Evolution equipped with a .0965 Class ZZ Pin Gage from Vermont Gage. The bores in the China wheels are so small they will not go on the pin. I put graphite in the bore and on the pin. When that did not work I put liquid soap on the bore and on the pin and it was still so tight I finally decided to simply force it on. At this point I do not know if I damaged anything regarding the wheel. I was able to turn the wheel and found the two I tested were from .005 to .010 out of round. Again, I don't know if I damaged something. I had to remove the wheels with a pliers thus ruining the wheels which I didn't care about to begin with. If someone is going to use the China wheels and intend to check them to see how round they are I think you will not be able to do it.
The Vermont gage measures exactly .0965 with my calipers. I can't picture that last "5" making such a difference that the wheel won't go on that pin, but maybe so.