Euro White 2" Cylinder Head Temperature Gauge (60 - 220 F)Perimeter-lighted White dial with bold Black 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" - Hole size: 2.0625" (53mm)Specifications:. Anti-scratch glass lens. Perimeter-lighted White dial. 12 VDC negative ground. Can be adapted for 24 VDC systems. Dual Scale - Metric and Imperial. Factory P/N GP9439*Sold as an Individual**Gauge Cover not Included