Light and compact structure, double shell body with air insulation, low surface temperature. High-precision microcomputer temperature controller and precision sensor are combined perfectly for temperature accurate control. Power is cut off when the door is opened, and power restoration is delayed to ensure safety. The auxiliary menu implements over-temperature alarm, deviation correction, menu lock, and over-temperature preventer. The vacuum-formed polycrystalline mullite fiber furnace is highly insulated, special alloy heating wires are heated on three sides to provide excellent temperature uniformity. Parallel side opening door keeps hot end away from operation. It is equipped with an exhaust device to facilitate ashing, and with function keys for temperature setting.