Plugs as in pellets???
http://www.hopsdirect.com/hops/pellethops.html
Yeah, half an ounce each, made to go in firkins for dry-hopping cask-conditioned ales, like this:
Incidentally, you might want to check out the website I stole that image from (first result from a google image search for "hop plugs"). They seem to sell to a lot of homebrew stores in packs up to a pound.
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