The other day I got a different type of Rubylith for my laptops.
I had been using Rubylith Acrylic Sheets while these worked good the new Rubylith worked a whole lot better!
It comes a heavy-duty plastic sheets that very easy to cut.
Its not as thick or as heavy as the Acrylic Sheets.
Since its not as thick I can leave on my laptop and close it with no problem.

it also works very well on lights and flashlights.

If you are still looking for Rubylith
scopestuff.com carries it!