It is a diaphragm-actuated, temperature-indicating gauge with a built-in electrical switch for tripping alarms and/or shutdown devices.
The gauge has a temperature range of 130-250°F (60-121°C).
The gauge pointer acts as a temperature indicator and as one switch pole, which completes a circuit when it touches the adjustable limit contact.
The device is designed for use in harsh environments, such as those found in the oil field, marine, irrigation, construction, and trucking industries.
It is used to monitor temperatures in applications like engine coolant, crankcase oil, and transmission oil.