The Tekmarnet® Thermostat 554 is a Communicating Touchscreen Thermostat Designed to Operate One Heating Stage, One Cooling Stage, And a Fan. The Heating Stage Can be Either Hydronic or Forced Air And The Cooling Stage Can Operate an Air Conditioner. There Are Two Auxiliary Sensor Inputs Available to Measure Room, Floor, Outdoor, Coil or Duct Temperature. The Optional Floor Sensor Allows Precise Heating of Radiant Floors by Controlling The Floor Temperature And Maintaining The Desired Room Air Temperature. The Large Touchscreen Allows You to Easily Adjust 7-day Programmable Schedules And Room Temperature to Optimize Comfort And Energy Savings. The 554 Can Connect to Tekmarnet Controls Using Two or Four Wires or it Can Operate as a Stand-Alone Thermostat Using Three Wires. For Further Information And up to Date Literature Visit: Tekmar Documentation | Tekmar Controls | 554