2 INCH WIDTH X 2-1/8 INCH DEPTH X 5-5/8 INCH HEIGHT SIZE; UL, CSA, AGA APPROVAL; HIGH LIMIT AND LOW LIMIT PROTECTION, BOILER, STORAGE TANK, DUCT APPLICATION; 120 TO 240 VOLT AC, 0.25 TO 12 VOLT DC VOLTAGE RATING; HORIZONTAL/VERTICAL MOUNTING