Low-cost box furnaces with a maximum working temperature of 1200°C. Furnaces exhibit excellent temperature uniformity and use a ceramic fiber board lining to ensure energy efficiency. Heating elements are designed in a unique configuration, which lays directly on a fiber-groove surface to ensure the longest heating element life, best heat radiation properties and minimum distortion of heating elements at high temperature. All models use long-life platinum/rhodium S-type thermocouple. 30-segment, easy-to-use PID programmable temperature controller, allows control of heating rates, dwells (time holds) and cooling rates. Safety feature includes a safety interlock system to shut off power when furnace door open. Max. Temp: 2192°F (1200°C) Chamber Dimensions (HxWxD): H-30214.4F: 4" x 5" x 8" (102 x 127 x 203mm) H-30215.4F: 6" x 7" x 8" (152 x 178 x 203mm) H-30216.4F: 7" x 8" x 12" (178 x 203 x 305mm)