FW Murphy, 10703966, A25 Series Temperature Gage, Explosion-Proofed, CSA Listed For Class I, Div. I, Groups C and D, Temperature Bulb Style D, 130 deg - 250 deg F (60 deg - 121 deg C)
It is diaphragm-actuated, temperature-indicating gages, with built-in electrical switches for tripping alarms and/ or shutdown devices.
It is fully sealed from the environment by the unique combination of a polycarbonate case and lens, a polished stainless steel bezel and O-ring seals.
This gage 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 a diaphragm mechanism. The diaphragm translates this vapor pressure into a mechanical gage reading.
It have internal snap-acting SPDT switches.
For more information, please see 
Data Sheet
