"Case" and "lid" you can pretty much print with any settings you want, and any material you want (i did .3mm, 3 shell, 15% infill black ABS).
The "lense" however must be printed special. You need a transparent filament, like clear natural PLA or PETG (i used PETG). To get a good difusion going, the lense model has specail internal structures (which normal infill patterns would mess up). Print this with 2 shells, 5 layers bottom, 4 layers top, and 0% infill.