Almost precisely modelled original diffuser.

STEP file is an "exact" model of the original diffuser you can tinker with.

The printable STL files are a bit altered to be print-friendly without supports.

The THIN version is with thinner diffuser walls. Normal is 2mm, thinner is 0.76mm to generate ideal two perimeter wall.

So if your filament is not quite translucent, use a thinner version.