An adjustable mechanical thermostat is a traditional device that allows users to regulate the temperature in a room or building. Unlike digital or smart thermostats, which often rely on advanced technology and complex settings, mechanical thermostats use a straightforward mechanism involving a bimetallic strip or a gas-filled bellows. These components react to temperature changes, moving a switch that controls heating or cooling systems. The thermostat is typically adjusted via a dial or knob, providing a simple yet effective way to set the desired temperature.