Rings Grommets

Where can I get this plug and what is its technical name?
Look at these photos please – http://www.flickr.com/photos/31355277 @ N03 /? Saved = 1 What is the black plug called? Is this a plug "shoulder" (or sholdered) or is it something else? The ring black is made of rubber plug that fits into a grommet, but I'm more interested in what the black cap called and where I can find and also a good place to get rubber washers. Any good shop or website recommendations? I need about 10 to 15 of these plugs as well as the same number of rounds. Thank you.
Thats a carnation do some hardware. If exact match is required, you may need to
