Forced air design for temperature uniformity, rapid cooldown and very fast recovery due to fan assistance. Fast temperature equilibration after door opening. Intelligent defrost mechanism through a thermocouple on the evaporator- only defrosts when ice foramtion detected. Controller displays data and control temperature and alarm setpoints. Stainless steel interior.Door lock. Unit provided with an automated voltage regulator. Units in use at vaccine research facilities and National Metrology Institutes.