The furnaces are constructed of aesthetic welded steel structures, low heat capacity ceramic fiber and lightweight brick masonry. The quality of the masonry depends on the temperature. The trolley version can be operated manually, in the front. Manually operated door that can be opened on two points. Automatic firing system equipped with high speed burners. The equipments are suitable for operation by natural gas or LPG. Programmed firing control, automatic neutral or furnace atmosphere reduction control.