July 21, 2008, with a UV Index between 11-12, I did an official experiment with my twin steel bowl cooker.
* A 3 cup pot & a glass lid (that I removed the plastic handle)
* A pyrex mixing bowl
* On top of the Bowl is a lid from an old crock pot.
The pot sits on a black candle holder, to elevate it off the bottom of the bowl. That is the shiny surface in the bottom of the bowl.
The bowl sits on what I'm guessing was a plate stand or plant stand of some kind. Having the bowl in this stand allows me to tip the bowl- as the cooker must be tipped to catch the sun- and still keep the pot level.