I did have only one cat that tried to scale the plexi. I just drapped the scat mat over the top and that particular cat never tried again.
I put black duct tape around most of it. It has a hook at the top and I filled that can with coins (Larry always throws his loose change in that can
A close-up of the filled can. I also at one point filled the can with rocks.
Here is a close-up of the bent hook Larry installed at the top. The plexi slides easily back and forth and the bent hook keeps it in place at the top.
A view from inside the foster room looking out. It also slides behind that dresser, but you don't need the dresser for this set-up. All that is needed, is the hook up top and something very heavy for the bottom by the molding. I have a scat mat on top of the dresser for the cats that think they can jump onto the dresser from the bed and then jump over the plexi from top of the dresser. They only try that once.
This is a view from outside the foster room looking in. Henry, my dog, and Pipsqueak are inside the foster room looking out
It has worked extremely well for us over the years and the plexi NEVER wears out and it easy to clean too.