Murphy 20TH-320-16-M10 Temperature Switchgauge (10701576)

20TH-320-16-M10: 2" Cylinder Head Temperature Swichgage®; 160-320° F. temp range; 16 ft. capillary length; 10mm x 1.5 adapter nut (10701576)

Cylinder Head Temperature 20TH are for use on Air Cooled engines.

The 20 Series (2 inch/51 mm dial) SWICHGAGE® models are diaphragm-actuated, temperature-indicating gages, with built-in electrical switches for tripping alarms and/or shutdown devices. 
The gage mechanism is enclosed in a steel case coated to resist corrosion. A polycarbonate, breakresistant lens and a polished, stainless steel bezel help protect this rugged, built-to-last instrument.
These vapor actuated gages feature a sealed capillary tube and a sensing bulb. When subjected to heat, the liquid in the sensing bulb changes to vapor creating pressure against the diaphragm mechanism. The diaphragm translates this vapor pressure into a mechanical gage reading. For series 20T, the gage pointer acts as a temperature indicator and as one switch pole which completes a circuit when it touches the adjustable limit contact. Contact(s) are grounded through the SWICHGAGE® case. They have self-cleaning motion to enhance electrical continuity.