Coral 2" Cylinder Head Temperature Gauge (60-120° F) with SenderPerimeter-lighted Black dial with stylish White and Blue graphics, Black aluminum bezel with burnished leading edge, 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:Scratch Resistant LensBlack Aluminum BezelContoured White PointerFactory P/N GP9405*Sold as an Individual**Gauge Cover not Included