Series 27 intrinsically safe controls have SPDT output contacts and are UL approved for use in Class I, Groups A, B, C & D; Class II, Groups E, F & G; and Class III hazardous locations. Control sensitivity is factory-set. Series 27 is UL Pilot Duty rated.  CSA certified for Class 1, Groups A, B, C and D; Class II, Groups E, F and G; Class III.