Nexthermal energy efficient cartridge heaters are constructed with a special high thermal transfer sheath material that creates a fast responding, longer lasting, more energy efficient heater. At the same rated wattage, Nexthermal is a leading supplier of cartridge heaters that have measured up to 25% improved energy efficiency over traditional build cartridge heaters.Our eheat cartridge heaters are the fast responding, energy efficient and direct replacements for your existing cartridge heaters. Extend the capabilities of your existing system