Hardening boxes are suitable for heat treatment under protective gas and are equipped with a protective gas intlet and outlet. For furnace models such as N 61/H with downward opening doors, the gas ductway is laid through the upper section of the door collar and for larger furnaces with upward opening doors, the supply line is laid through the lower furnace collar.

• Protective gas box with lid, protective gas inlet and outlet through the furnace collar and seal profile
• Maximum temperature of 1100 °C
• Charge thermocouple type K