allows brewing coffee on the go - place on top of a mug, put disposable filter and coffee inside, pour hot water
Pretty useful for brewing real coffe...e in a hotel room that provides a water heater and instant coffee, while camping, or even at home if you only need a cup.
The photo with the filter shows an older version with holes in the sides; the side holes proved useless in practice, made for huge render / slice times and slowed down printing, so they're gone from the latest design.
3d model print parameters
I printed mine with transparent Colorfabb XT, but any food-safe filament with a high Tg should do (XT is at the limit, the bottom buckled a little)....