With workspace dimensions of 30 x 48 x 30 in., electrically heated No. 989 uses 57 kW nickel-chrome wire coils supported by vacuum-formed ceramic fiber. Roof-mounted, heat-resisting alloy circulating fan, powered by 2 hp motor with V-belt drive, maintains inert atmosphere for workload. Furnace includes continuously welded outer shell, 7 in. thick insulated walls, 7½ in. floor insulation, and electrically operated vertical lift door.