What do you call the metal that blocks PCI Express ports on a computer case? Where can I buy them?

I'm always running into the issue of never having enough of those little metal guys to replace on a PC case. I'd love to have a collection for those occasions when the manufacturer fails to provide replaceable pieces.What do you call the metal that blocks PCI Express ports on a computer case? Where can I buy them?
They are called ';Blanks'; or Expansion slot covers I think. As far as finding a place that sells them, try Radio Shack or a local computer repair shop.What do you call the metal that blocks PCI Express ports on a computer case? Where can I buy them?
Expansion slot covers. This is one place I found real quick: http://www.compusa.com/products/product_鈥?/a>