This is a magnetically attached vent deflector suitable for ceiling mounting, too. Magnets are 8x3 neodymium, this is the pack I bought (200 for $13.99) https://www.amazon.com/gp/product/B0CCXH6W5Q
I used PETG since it will have hot air blowing on it in the winter.
There is also a combined STL where they can both print at the same time, this will fit pretty easily on a smaller bed (160x160).
The author marked this model as their own original creation.