Round windows for a fairy garden. Two sizes: 35 mm diameter and 70 mm diameter. Screw hole in the middle for mounting. Small overhang / top cap to window.
I printed mine using PLA, which I then painted with exterior/house paint. They're in a shaded area and should last. PETG should last longer if unpainted or in direct sunlight.
I printed at a 0.1 layer height but 0.2 should work as well (just not as detailed).
The author hasn't provided the model origin yet.