They are screen cover clips that you could find at any pet store. They look like this: http://www.strictlypetsupplies.com/_...er-Clips-Large
I use binder clips for my tubs, but they don't work with metal screen tops.
Actually the WORST sound in the world to me, worse than nails on a blackboard is the squeaking of styrofoam rubbing together. I can't stand it. So I personally wouldn't be able to do something like this... But it is a neat idea. The only thing I'm concerned about is wouldn't the snake be able to snap off those styrofoam ledges? If something is possible, my corn will figure out how to do it in the first day
Thanks, didn't know that. I'll have to check that out.