This series of constant temperature and humidity test chambers is mainly designed to simulate the harsh high-temperature, low-temperature, damp and hot environments that electronic instruments and meters, new materials, electrical engineering products, vehicles, metal products, electronic products, aerospace materials and other items may encounter during transportation, storage and use. It can also be used to test the high temperature resistance, low temperature resistance and damp heat resistance of materials, accessories or instrument equipment, as well as potential damage and service life reduction of the tested objects under alternating high-temperature, low-temperature, damp and hot conditions.