Chesapeake White SS 2 Water Temperature Gauge 100-250 DegreesF . 2 Hole Size 2.0625 53mm . A temperature gauge operates by sending a low amperage current through the gauges's meter to ground via a sending unit with variable resistance. The resistance of the sending units increase or decrease with the changes in pressure, temperature, etc. As the sender's resistance varies, the amount of current allowed to flow through it to ground changes and the meter deflects, showing the temperature. Available for MG systems, J1939 CAN Bus or J1939 Stand-Alone systems and mechanical types. Benefits Standard 100-250 degrees F . Metric 40-120 degrees C . Dual Scale. With or without Warning Lights 2 Hole Size 2.0625 53mm . A temperature gauge operates by sending a low amperage current throu As the sender's resistance varies, the amount of current allowed to flow through it to ground change Benefits . Standard 100-250 degrees F Metric 40-120 degrees C . Dual Scale With or without Warning Lights