Because of the tubular structure design, the winding space utilization rate is high, the coil part is open, the heat dissipation effect is good, and the magnetic lines of force are maximized. The use of high magnetic permeability materials and a conical magnetic circuit structure is a type of electromagnet with saturated magnetic circuits. Most of the electromagnetic energy is converted into magnetic energy. Although the product is small in size and light in weight, it has a larger stroke and attraction than conventional small electromagnets, and has the characteristics of high power and long life. The round tube electromagnet has a unique design shape, more stable characteristics, more reliable operation, and easier installation. In addition, the round tube shell provides good protection and anti-corrosion for the internal electromagnetic components, making it very suitable for use in small spaces and harsh environments.