Like the title, I have a small DIY project where I’m going to put a gerbil tunnel system connecting two of the enclosures in the image together. Because the transparent window is thin clear plastic they aren’t really strong enough to handle any force at where the tunnels will connect to the windows.

So, I want to put stabilizing bars connecting both enclosures together at their frame. I’m thinking like a 1”x1” hard plastic bar, that’s 6”-12” long, at the corners of the window that lock into square plates that have three sides lifted (“c” style) to slot and lock the bar into. I don’t know what this would be called. Idk where I would find it. But, this seems like something I’ve seen before and should exist.

Does anything come to mind?