The White-Rodgers 1F56N-444 thermostat is an easy to operate low-Voltage mechanical thermostat. The 1F56N-444 provides accurate temperature control that is easy to use. The 1F56N-444 is for use on single stage furnaces, air conditioners and heat pumps. For use on 24-Volt and mill volt systems. The 1F56N-444 is a mercury free thermostat. White-Rodgers is a business of Emerson Climate Technologies, the world's leading provider of heating, ventilation, air conditioning, and refrigeration solutions for residential, industrial, and commercial applications. Combining technically superior products and services from industry-leading companies and brands with global engineering, design, distribution, installation, and monitoring capabilities help Emerson Climate Technologies to create reliable, energy efficient climate systems that improve human comfort, safeguard food, and protect the environment.