Electronic Temperature Reset Control Raises or lowers the temperature of the supply water or air based on a proportionate rise or drop in temperature at the outside sensor. Output relay SPST, N.O. includes LED indication of both relay status and night setback mode. The A350 requires a 24VAC power source and features a differential range of 1°F to 30°F and can be used alone or in conjunction with other modules. Adjustable reset ratio 1:5 to 3:1 (outdoor/indoor) Temperature Reset 2.4" x 2.4" x 5"