Laboratory refrigerators and laboratory freezers are used to cool or freeze samples for preservation. Typically, a laboratory refrigerator stores samples at a temperature between - 5 and 15 degrees Celsius. A laboratory freezer stores samples at a temperature between - 25 and - 15 degrees Celsius. Some laboratory freezers are used to store biological samples such as vaccines at a much lower temperature. Cryogenic freezing is also used in laboratories, but requires specialty equipment that can generate and tolerate extremely low temperatures.