This is a temporary 100mm vent pipe cover making a tight friction fit with the pipe. The mesh keeps out insects. The project I used this in can be found here: https://jamesdaniel.github.io/bathroom_vent_project.html. I printed this model using PLA filament on my Creality Ender 3 printer. I did a quick print with thin walls so it would print quickly and it's only temprary.