24 Volt or Millivolt, Heat Only - Gas, Electric, or Oil, Square, Designed as a Replacement Unit For Mechanical Thermostats, Easy Do-It-Yourself Installation, Calibrated Thermometer, No Leveling Required, Environmentally Friendly, Easy-To-See Adjustment Scale, Large, Easy-To-Hold Switches and Adjustment Lever, Adjustable Heat Anticipator, Microswitching System, Dust Sealed Mechanism, Includes Decorative Wall Plate