Cartridges that have a low voltage charge are mostly used for heating up to 300ºC. They are made with stainless steel tube of the best quality, or with copper, brass and aluminium. Everything about these cartridges has been calibrated in the perfect way. A long lasting ceramic piece is inserted into the tube and it is able to stand up against every sort of temperature variation. The piece will be in contact with the tube wall thus ensuring even heat distribution. The quality heater wire is inside the ceramic piece. The nickel-chromium heater wire is suitable for cartridge heaters. Checked granulometric magnesium oxide covers the inside of the cartridge heater. Perfect conductivity is obtained between the heater wire and the heater.