Plenty of other options out there doing the same thing. None fit my window very well. I would not use this for high temperature applications like venting air conditioners or dryers, unless you print with appropriate filaments. 

Designed for venting my Gweike G2 laser and/or 3d printer out the window. I started printing “blank” filler blocks (blue piece in photos) to eat up the remaining window space, then realized foam posterboard is cheap and way faster than 3d printing, so I made adapters to allow foam board to be cut and assembled to block off the unused window space. Printable pins snap in between pieces to hold them together.

One vent, two foam board adapters, and two pins should cover most applications. If posterboard isn't long enough to fill your window, you can print two more foamboard adapters to bridge the gap, or I can upload my “blank” file if you feel like wasting filament like I did :)

Check your window dimensions before printing. This fits my window well enough I can leave the vent in place with the window open and it won't fall out, at nominally 1" thick.