FW Murphy, 10701041, SDB Series Direct Mount Temperature Gage with Adjustable Limit Switch, 100 deg to 500 deg F, 2 A at 30 VAC, Die-Cast Aluminum Case
It provide an accurate direct-reading gage with an adjustable limit switch to activate alarms and/or shutdown. A knob on front of the instrument allows you to adjust the limit switch trip point. Pointer movement is actuated by a bi-metallic sensing element.
The most common use of the Gage is to monitor gas compressor temperatures. Engine exhaust temperature can also be monitored to indicate overloading or lean fuel mixtures, or use the SDB to help coordinate loads on twin-engine installations.
For more information, please see 
Data Sheet
