Superior Life Expectancy. Highly Non-corrosive, various watt Density option available, standard sizes available, specially selected High Purity Magnesium Oxide. Low density cartridge heaters are developed for heating applications not requiring high watt densities not surface temperatures exceeding 300Â°C, with maximum watt densities of 30 to 45 watts per square inch depending on applications. The heaters of various surface diameters can be used in any assembly, equipment or machine. The heater design consists of a helically wound resistance coil made from nickel-chrome wire, evenly stretched & strung through holes in a round ceramic insulator. The element assembly is inserted into a chrome nickel steel. This alloy provides the best combination of physical strength & resistance to heat oxidation up to 450Â°C.Specially selected grain size & high purity magnesium oxide is used to fill all remaining space inside the ceramic insulator to increase thermal conductivity, dielectric strength, & provide longer operating heater life. The heaters are used in operations involving packaging machinery, labelling machines, plastic injection, shoe machinery, heat sealing, hot stamping, glue guns & wax pots, heating of gases & liquids & various other heating applications.