I bought the same one as @cyclone86 from Aliexpress and I’m very satisfied with fit of the axel adapter into axel and the mud guard itself that goes over the rear tire. It’s solid made out of anodized aluminum and the mud guard made of plastic does not move a bit.
The only thing I did not like are the 4 markings on the adaptor, compared with six markings on the standard axel adaptor. That makes it harder to get the tire perfectly aligned into the rear axel as these markings give an idea how far the adaptor is in the axel. Not a big deal and compared to the price and quality I’m super happy. Forgot to mention that mine has ‘GS’ carved in pretty big letters on the adaptor. The mud guard itself has a ‘900 XR’ sticker on it.