Chesapeake White SS 2 Cylinder Head Temperature Gauge 60-220FPerimeter-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 gauges 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 53mmSpecificationsA