I have a slide door that I want to add a cat flap to, but most flaps are too wide for the “spare room” on that slide door and I happened to have a Car Mate Glass fitting Cat Flap" lying around.

I added a piece of 18mm 20cm laminated bookshelf to the slide door and designed this as an extension to fill the “hole” left in the bottom.

The current print is in black (yay for SUNLU recycled PLA), a white one is currently being printed.

I inserted a 9x9x9cm neodynium magnet in the bottom, as I was unable to pry the original magnet out of the original frame.
I greased the “bolts” on the side of the door with a bit of Lithium Grease, which I normally use for my Z-rails ;-)