Anemometers, or wind gauges, are available in two technologies: vane anemometers and hot-wire anemometers. Hot-wire anemometers are thermal anemometers with exposed hot wires. These measure changes in wire temperature via heat lost as it is cooled by the wind, which is converted into fluid velocity. Vane anemometers combine a wind vane for airflow direction with a propeller-like device that measures wind speed. Hot-wire anemometers are more common due to the wider airflow range measured.