The JISICO Electric Muffle Furnace comes in three model sizes with capacities of 4.5, 14, and 63 liters. The heating elements in these furnaces are installed in the four sides within the walls. This prevents contamination of specimens by corrosive gases or water vapor, as well as helping to ensure longer life of the unit itself. Control of the unit is by means of a PID auto-tuning device which enables both digital control settings and display. Air circulation within the twin-wall structure of the unit keeps the outer surface of the furnace cool. The controller is protected by a heat-resistant panel.