The Lid and Bottom
You can separate the firebrick top and bottom from the Caldera. This makes the kiln modular so that you can add a collar, which is a kiln section that adds depth to the firing chamber. The collar is inserted between the kiln bottom and the Caldera. We have three types of collars:
The blank Caldera-X, which adds 4 1/2" of depth
The Caldera-BC, which adds 4 1/2" of depth and includes a bead door for annealing
The Caldera-E copper enameling collar.
The FireFly has a built-in brick bottom and a hinged lid. A collar cannot be added to the FireFly.
Both kilns can be ordered with the optional 2" x 2" high-temperature glass window, which is centered in the lid. The window lowers the kiln's maximum temperature to around 2100F.
Both kilns have a safety switch, recessed element grooves, L-notched corners, case tighteners, and the Sentry Xpress with Cone-Fire and 8-segment Ramp-Hold modes.
Both kilns are rated to 2350F and plug into a 120 volt, 5-15R wall outlet.
Both kilns are 8" x 8" inside; the Caldera is 6 3/4" deep, and the FireFly is 4 1/2" deep. The Caldera, without collar, offers a 2 1/4" deeper firing chamber.