New-old stock VDO 12V gas engine 250 degree (120 Celsius) temp gauge (engine water temperature) for an older boat or could possibly be used on a Motorhome or truck. Part number 1 231 015 104. Gauge is electric and has spade type terminals for hooking wires to, not threaded terminals. 

2-1/8" OD and fits in a 2" diameter dash hole opening.

Includes mounting bracket and light bulb