“Found these clumps of fibers in my apartment and at first thought they were cat hair, but they are too thick and break easily when bent.”
“It was deer hair from a cat toy — my cat sitter brought this attachment, and my cats stole/destroyed it. I had no idea they made cat toys with deer hair!”
Not so much as a stamp, as a printing plate. Before ink jet printers, they would ink these up, and press paper against them.
The dial on the right sets the resistance in Megaohm as far as I can read. If I see that correctly its the printing plate for manual for an old X-Ray machine. Only those kathode tubes (at the bottom) would akquire such high voltage (200V)