How to install a cat flap into a window without getting a glazier

Here is my go to solution for renters wanting a cat flap. It's the cheapest and most DIY friendly solution I know of.
What do you think? Any way to improve this?

[@Susan-gh6gx]

Thank you so much! Just what I need and can’t afford the pre made ones $150 and up! Now I just have to find someone to make it for me. Already have the door!you are a genius!

[@qbobites8450]

We weren’t sure what to do with our catio window, and we saw your video. It saved us! We love it so much, thank you!!

[@susetramsauer177]

This is excellent!! I knew what I needed to do for the Catio window just wasnt sure about execution!!! Thank you for posting

[@inluminance]

Genius!! Thank you for sharing this 👍

[@Kt-ux2ez]

Clever! Thanks 😎

[@lisalegrand3171]

Thanks so much!

[@georgewashington3555]

THANK you ! need to find the corflute now and try to make it.

[@pandabear4256]

That’s so smart!

[@yarblar]

What thickness of perspex/coreflute do you use here? Thank you!

[@shibibi1]

But what about putting the Flys reen back? 😬

[@TraceeBeebe]

What is that plastic called? I’m not familiar with the word he’s saying

[@lisalove7147]

I think it maybe Polycarbonate panel

[@jackiegonzales7980]

Corflute is corrugated polypropylene - a type of plastic - usually 3mm or 5mm in width. You'll most likely have seen corflute signage used as part of political advertising, by real estate companies advertising local homes, or on temporary construction sites - Home Depot sells a 12 x 36" piece, transparent, for about $13

[@stopthephilosophicalzombie9017]

Sort of defeats the security of the window, doesn't it?