The No. 790 box furnace is electrically heated to a maximum operating temperature of 2200F (1205C) and has workspace dimensions of 24 in. wide x 36 in. deep x 18 in. high (610 x 915 x 460 mm). Total power of 36 kW is available using Kanthal AF alloy wire, rod overbend design, providing constant, even temperature to the workload. The unit features a digital display temperature controller, manual reset excess temperature controller with separate contactors, five-hour shutdown timer, phase angle-fired SCR power controller, integrally mounted power transformer, and a single-pen strip chart recorder. The 9 in. (230 mm) thick insulated walls comprise 4.5 in. (115 mm) thick 2600F (1425C) firebrick, 2.5 in. (65 mm) thick 2300F (1260C) firebrick, and 2 in. (50 mm) block insulation and a firebrick plate hearth supported by firebrick piers.