Honeywell CT87N The Round Non-Programmable Thermostat offers a classic, reliable design for controlling heating and cooling systems. This mercury-free mechanical thermostat features a familiar circular interface that is easy to use and install, typically taking 15 minutes or less. It includes a wall cover plate to hide marks from previous thermostats and comes with all necessary mounting hardware. Designed for basic operation, it provides precise temperature control without the complexity of programming, making it an ideal choice for those who prefer manual adjustments. Note that it is not compatible with electric baseboard heat (120-240V), heat pump systems, or multi-stage heating/cooling.