The cost effective alternative for high watt density heaters or Pencil Heaters greater than 7” long with watt densities below 65 watts per square inch and for high temperature applications which do not require precise watt distribution.Nexthermal medium watt density heaters can now be built with internal Type J or Type K thermocouples.  Medium watt density cartridge (pencil) heaters have the resistance wire in the center of a ceramic core . Swaged in the same method as our high watt density cartridge heaters - Medium watt density cartridge (pencil) heaters are durable workhorses.