Thermal mass flow meters are devices used to measure the flow rate of gases and liquids. They operate based on the principle of heat transfer, where a heated element is placed in the flow stream. As the fluid flows past the heated element, it carries away heat, and the amount of heat lost is proportional to the mass flow rate of the fluid. These meters are known for their accuracy and reliability in various applications, including industrial processes, HVAC systems, and environmental monitoring. They can measure flow rates without needing additional pressure or temperature corrections, making them efficient for many settings.