Tubular heaters have the longest lifespans of any heater. A heating coil is inserted into a metal pipe, and MgO powder is used to fill the space between the metal pipe and heating coil to create a tubular-shaped construction. This heater is used in a variety of applications due to its flexible shape, which is one of its major features. It is widely used in many fields to heat both gas and liquid, not to mention defrosting.