The laying electrical heating tubes are more widely used in various household appliances and industrial electric heating equipment compared to resistance wires. Their structure involves placing pre-wound spiral wires inside a metal tube, which is then tightly filled with magnesium oxide powder with good thermal conductivity and insulation properties in the gap between the spiral wires and the tube. The tube is sealed with adhesive for insulation. This type of metal electric heating element can heat air, metal molds, and various liquids (water, oil, acidic or alkaline corrosive liquids). The electric heating tubes are characterized by their simple structure, high mechanical strength, ability to be bent into various shapes, long service life, energy-saving properties, easy installation, non-pollution, and high thermal efficiency.