Features Elements are designed for maximum: Watt density, temperature, heat transfer, and heater life. The useful life of a cartridge heating element is determined by how quickly the heat generated in the resistance wire can be dissipated to the outside sheath. With low and moderate watt density elements, the conventional method of inserting helical coils in formed ceramics is an entirely satisfactory method of construction because the wire temperature relative to sheath temperature even though considerably higher, is still well within safe long-life operating temperatures. The Superwatt cartridge heater accelerates the transfer of heat from the resistance wire to the sheath. This is accomplished by relocating the wire so that it is closer to the sheath; and swaging the outside diameter of the heater, thereby compressing the magnesium oxide filler so that it becomes an improved conductor of heat from the wire while maintaining its dielectric properties. (See diagram below). By improving the heat transfer rate, it is possible to manufacture elements of higher densities because the differential between the wire temperature and the sheath temperature has been minimized. Long, trouble free service.