Furnaces feature ceramic fiber insulation for fast heat-up and reduced energy consumption—rise time to 1100°>C takes only 50 minutes. Embedded heating elements on three sides give an improved temperature gradient. Drop-down door serves as a convenient shelf for loading and unloading samples. A safety interlock switch disconnects power to heating elements whenever the door is opened. Chambers are constructed of heavy-duty welded steel. Order optional hearth plate separately.