Professional Red 2" Water Temp (100 to 250Adeg F)Perimeter-lighted black dial with stylish Red and White graphics, Black aluminum bezel, tear- drop White pointer, and flat glass lens.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, ect.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.2"- Hole Size: 2.0625" (53mm)Specifications: Flat Glass Anti-fog, Scratch Resistant Lens Black Aluminum Bezel White Numeric Values with Red Increment Indicators White Tear Drop Pointer Dual Scale - Imperial and Metric Factory P/N GP7166*Sold as an Individual**Gauge Cover not IncludedThis product may not be returned to the original point of purchase. Please contact the manufacturer directly with any issues or concerns. Specifications: Gauge Type: Water Temperature Gauge Size: 2" Series: Pro Red Box Set: No Voltage - Input Range (Volts): 12/24 V Box Dimensions: 4"H x 4"W x 5"L WT: 0.3 lbs UPC: 759266146044