Low Voltage Thermostat, Terminal Designations R, W, System Switching No, Fan Switching No, Automatic Changeover No, Dual Transformer Compatible No, Power Method Hardwired, Voltage 20 to 30V AC, 750mV Compatible No, Mounting Vertical, Height 4 3/4 in, Width 2 7/8 in, Depth 1 3/8 in, Color White, Control Range 50 Degrees to 90 Degrees F, Features Mercury Free, Integrated thermometer, For Use With Gas, Oil, Forced Warm Air, Hot Water, Steam or Gravity, Includes Hardware