This object was made in Tinkercad. Edit it online https://www.tinkercad.com/things/5RK4s3T6epN

I needed to keep the door open a small amount to let the cat in and out when the Air con was on, I used 4 small nails to attach it to the top of the door frame.

Use 20mm Magnets, they should slip on and I use a little super glue to hold them in.