FAQ:
The anomalies models are made of translucent plastic; the bases though are cast from regular, "grey" plastic.
If you'll choose the non-sundropped variant, you'll get them without the sundrop (clear, translucent models of anomalies on grey plastic bases).
With sundrop selection, the bases will be sundropped to match the rest of models, and the anomalies itself coated with a subtle wash layer, enhancing the sculpt, yet keeping the translucent effect on the models.