White Rodgers Heat Only Mechanical Thermostat works seamlessly with single-stage heating systems, supporting both 24 volt and millivolt configurations. It is compatible with a variety of heating types including standard heat only, millivolt heat only systems such as floor or wall furnaces, gas or oil heat, electric furnaces, and hydronic hot water zone heating that uses 2 wires. Designed for easy installation and user-friendly operation, this thermostat comes with a decorative wall plate, mounting hardware, and a comprehensive installation guide. It is mercury , ensuring safety and environmental friendliness, and backed by a 1-year warranty. The thermostat is off-white in color and packaged in a clamshell for protection. Model Number: M30