Chesapeake White SS 2" Cylinder Head Temperature Gauge (60-220F)Perimeter-lighted White dial with stylish Blue and White graphics, polished stainless steel bezel, contoured White pointer and domed 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 back light. 12 VDC negative ground. Can be adapted for 24 VDC systems. Dual Scale - Imperial or Metric. Factory P/N GP9454*Sold as an Individual**Gauge Cover not Included