The #918 furnace features a programmable controller with three built-in, easy-to-use programs plus the ability to be custom-programmed for your own burnout schedule up to 99 hours, with delay start capability. Controller allows you to preset up to 20 segments or "ramps." Each ramp consists of (1) rate of heating/cooling, (2) temperature setting in °F or °C, and (3) hold time for each temperature. The program you set stays in permanent memory until you reset it. Furnace is enclosed in a tough stainless steel cabinet with a firebrick lined chamber. Easily replaceable heating elements are secured in grooves inside the chamber.