These furnaces have 4” thick side walls, floors, and ceilings. The frame is built of sturdy angle iron, and the outside is stainless steel. Plain and simple to rebuild the insides, also replace elements. Inserting crucibles or cupels is done easily, without heavy heat loss…These are some of the reasons we’ve been selling this furnace, almost exclusively, for the past 30 years. The temperature rating is 2300° F continuous operation, which means you will have a little extra margin for those unusual experiments. We have seen some of these furnaces that have lasted for many years. The extra thick walls make this furnace very energy efficient. Our belief is that you can not find a better built electric furnace for assay purposes at any price. All models are now furnished with a digital temperature control. With a little practice the operator can set the control to maintain any given temperature. Temperature is maintained within 2° using the Automatic Control. Ships by LTL truck only.