This is an adapter for an aircon tube (portable air conditioning device). Mine's brand is Electrolux. It just slides in (vertically, from top to bottom) and stays there perfectly fine. This makes moving the aircon around easy and allows inserting/removing the tube.
I have a sliding door adapter (custom, made out of wood and some 3d printed parts) and I bolted this on the adapter. It has a whole to let the air out of course. I could have built this out of wood as well, but 3D printing is just easier.
I used ABS and a 0.8mm nozzle to speed things up. Detail is not very important for this print.
aircon-adapter-AB.stl | 2.3MB |