This is extremely tough. I tried the Williams-Sonoma site, and even the Cookware's Association site, but could not find this pot.

I would say graduated, or with a graduated base, but that's not authoritative.

This is tough indeed!
Anyway, the shortest description I came up with is the above...a mere guess.

An insert for a crock pot having an interior compartment and an upper rim, the insert comprising: a body formed of aluminum foil and having a bottom and vertical sidewalls with a shape that conforms to the interior compartment of the crock pot; a flanged rim extending out from an upper portion of the vertical sidewalls and disposed to engage and rest on the upper rim of the crock pot; and a vertically disposed divider extending between and connecting the bottom and interior portions of the vertical sidewalls to form a first food compartment and a second food compartment.
http://www.freepatentsonline.com/20020038802.html

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Note added at 5 days (2007-07-09 18:24:23 GMT)
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Thank you, Jen! Now at least we know what to ask for if we will ever need in life a pot like that.. :-) ..which, in my case, it's never gonna happen: I don't cook that much and my 2 pots (a big and a small one, respectively) are more than enough!
Ciao!