Cryostats are used to maintain low cryogenic temperatures of samples or devices mounted within the cryostat. Low temperatures may be maintained within a cryostat by using various refrigeration methods. True cryogenic temperature are most commonly attained using cryogenic fluid bath such as liquid helium while double-stage compressor systems are capable of cooling samples down to -100 °C using only electrical power. Cryostats have numerous applications within science, engineering, and medicine.