Car Water Temperature Gauge 2 Inch for 12 Volt System UniversalCondtion Air core meter moverment Suitable for 12 volt systems Mounting directly in 2 inch hole Scale from 100F to 250 F 40 ℃ to 120 ℃ 2 inch water temperature gauge with backlight Come with black metal panel and U bracket for add on or replacement purpose It can alert you that higher or lower than normal water temperature reading to protect your driving safe How to Connect Red wire lead for volt supply to internal lampBlack wire to system groundS Threaded terminal for connecting sensor wire Threaded terminal for connecting volt supply Threaded terminal for connecting system groundPls remember that the sensor is automatically connected to system ground when installed If installing where the body of the sensor is not tied to system ground it will be necessary to hook up a ground to the body of the sensor element Note Hole diameter is 2 inch Meter OD is 2 3 16 inch Meter depth from front of panel to the end of the mounting studs is 2 inch All you will need is 18 gauge stranded wire to make the necessary connections Package Included 1 X Water Temperature Gauge1 X Sensor1 X Manual