LEFOO differential pressure products can monitor the change of indoor air pressure and can be used to detect the gas pressure in the clean ward of the negative pressure ward. The current HVAC system generally circulates the air to achieve the purpose of energy-saving, which will cause the indoor oxygen low concentration, and poor breathing may cause chest tightness, nausea and other symptoms. Some influenza viruses will be more active indoors with low relative humidity and high temperature, and the survival period will be longer. LIFO's carbon dioxide transmitter can monitor carbon dioxide in the air. Concentration, temperature and humidity transmitter can monitor the temperature and relative humidity in the air, temperature and humidity transmitter can also be used to monitor the storage conditions of medical equipment, T2000 can be used for medical gas leak alarm.