Lowest chamber is a heat diffusion and thermal storage mass area. Heat enters the chamber from the firebox, but can only rise into the cooking area through the 8" diameter hole in the center. Not shown is the firebrick lining the floor and three sides of the lower chamber. Also, the "roof" of the chamber (or floor of the cooker) with the 8" dia. hole is constructed of 1/4" steel plate.

The cooker is constructed of 16 gauge steel sheet metal inside and out over a steel tube framework and insulated with a combination of high temperature fiberglass insulation board and ceramic fiber batt.

The cooking chamber is equipped with six removeable cooking grates, for a total cooking area of at least 2,800 square inches.
Note: Only two grates are shown for clarity.