There are two categories of ultra-low temperature series, namely air-cooled box type and water-cooled box type; The outlet temperature of the refrigerant is adjustable from -90℃ to -120℃, and the cooling capacity of the single machine is 1KW to 50KW for selection. The refrigerant flow rate depends on the working condition and cooling capacity. The product is completed in the factory, after testing various indicators, filled with refrigerant, and then through water and electricity power to start commissioning, to ensure that all parameters are qualified before leaving the factory.