The Admiral Blue Belle gas heater is equipped with an open flame and a thermostat. When the desired temperature is reached, the flame decreases from max. to min., but does not switch off. The built-in oxygen deficiency safety device monitors the CO2 content in the environment and switches the oven off automatically if the intended standard limit of 1.5% is exceeded. The heater produces neither CO nor unburned gas and is therefore eco-friendly. The heat is created by natural air circulation.