Portable AC Window Seal Kit for Casement & Crank Windows, 300CM/118" No-Drill Window Vent Kit, Adjustable Zipper Seal for Single & Dual Hose Portable Air Conditioners, Waterproof AC Window Kit

https://a.co/d/06FQ4NC7 "400CM(157") Window Seal Kit, Casement AC Window Vent Seal Kit, Sealing Effect Waterproof Window Seal Kit, Easy Installation, Fit for Single&Dual Hose 1~6in Portable Air Conditioner, Tumbler Dryer" Hope this helps!

Man, here’s me wondering if someone could make an accordion-style insert that could fit in the window while still keeping some measure of security. I wonder if someone has already? EDIT: Holy fuck they HAVE! 😃 https://a.co/d/025gEhue

You just need one of these: casement window portable AC vent kit