"LUX PRODUCTS CORP" ROUND HEAT/COOL THERMOSTATPresenting the Lux Eco-Stat, a highly accurate, mechanical thermostat that makes home heating and cooling easy and eco-friendly. That"s because Eco-Stat is MERCURY FREE which makes for a better, cleaner environment.The Eco-Stat also features a push button backlight for better readability in any lighting condition, and both a soft-touch rubber set-temperature ring and large mode switches for easy operation and temperature adjustments. For use on most 24 Volt Heating & Cooling Systems.Good for 2-wire Hydronic Hot Water Baseboard & Radiators Systems. Not for use on Heat Pumps.Wall plate shown is included but using it is optional. Highlights :-Push button backlight Mechanical Heat & Cool Thermostat Soft rubber Set Temperature Ring Large easy to use Mode Switches Needs no batteries