The Series 27 features SPDT output contacts and is UL-CSA Approved, UL approved for use in Class I groups A, B, C, D, Class II groups E, F, G, and Class III hazardous locations.  The Series 27 is also UL Pilot Duty rated and CSA Certified for Class 1 groups A, B, C and D, Class II Groups E, F and G and Class III.