Window:
Material: Perspex Opal (light emissivity: 28%)
Thickness: 3.0 mm
Supplier: https://kunststofplatenshop.nl/product/plexiglas-opaalwit-3mm/

M3 inserts:
Insert outer diameter: 4.9 mm
Length: 6.0 mm
Supplier: https://www.123-3d.nl/123-3D-Schroefdraadbus-M3-10-stuks-i1687-t9745.html

M3 screw:
Head diameter: 6.0 mm
Conus: 45 degrees
Supplier: https://www.123-3d.nl/123-3D-Metaalschroef-verzonken-kop-M3x6-verzinkt-50-stuks-i1260-t3135.html