Faria Euro Black 2" Cylinder Head Temperature Gauge (60 to 220 F) with Sender [12819]Euro Black 2" Cylinder Head Temperature Gauge (60 to 220 F) with Sender Perimeter lighted Black dial with bold White graphics, Black aluminum bezel, contoured White pointer, and flat glass lens. A temperature gauge operates by sending a low amperage current through the gauge's meter to the ground via a sending unit with variable resistance. The resistance of the sending units increases or decreases with the changes in pressure, temperature, etc. 2"