WarmlyYours SmartStat 7-Day Programmable GFCI Thermostat, with Floor Sensor (120V/240V) BUILT-IN GFCI: Features a built-in GFCI for safety and accommodates either 120V or 240V floor heating systems, for radiant floor heating installation larger than 240 sq. ft., a Master Thermostat with Power Module or a Relay Contactor is also required INCLUDED FLOOR SENSOR: Complimentary 10K ohm floor sensor allows for energy efficient operation of your electric floor heating system, the sensor is installed in the floor and connects to a thermostat MODERN DESIGN: Features a large, backlit digital display that makes it easy to read in low light areas, also features battery backup in case of power failure, in the event of an power outage, the built-in battery will provide up to 2 hours of operation PROGRAMMABLE: SmartStat allows you to program up to 4 setting changes for each day of the week and includes manual setbacks to "high" and a "low" temperature levels, which means you can customize your comfort while cutting down on operating cost EARLY START MODE: Allows the thermostat to self-learn what time it needs to activate the system to ensure the floor is warmed to the desired temperature at the time you programmed