Review on Sigma 16Mm Contemporary Lens Sony by Somchai Promsombat ᠌

Of course I'm sorry, this is my first purchase of Sigma products. The only thing I don’t understand is what large dust particles do inside the new lens, there is not one dust particle, I counted a total of 4 pieces, they are of different sizes and on different lenses, they go deep into the lens. I did not tempt fate and returned the lens back, I did not put it on the camera. I examined the dust particles under a magnifying glass, they are very similar to ordinary silver sequins. If I'm wrong and this is normal for Sigma lenses, please correct me, otherwise I may not understand something.