The 017-502166 RT6AES Danfoss pressure switch units are designated for industrial refrigeration and general industrial application in explosive zones acc. to 94/9/EC, Atex directive, explosive zone 1, for surface equipment, category 2. It includes usage in refrigeration systems with ammonia, hydro carbons and other applications where presence of flammable gases, vapours and mists are likely to occur. 017-502166 RT6AES Danfoss pressure switches for use in explosive zones incorporate SPDT changeover switch where contact position depends on pressure or temperature value of the system.