Keep an eye on the temperature of your boat's engine coolant to prevent it from overheating and causing major engine problems. The H20 GAUGE (F12812) is constructed with a scratch-resistant glass lens that can withstand any marine environment. The H20 GAUGE (F12812) is a temperature gauge that operates by sending a variable resistance unit with a low amperage current through the gauge's meter to the ground. The resistance of the sending units increases or decreases as pressure and temperature change. As the sender's resistance changes, the amount of current flowing through to the ground changes, and the meter deflects and displays the temperature. Key Features: Constructed with a scratch-resistant glass lens that can withstand any marine environment It has a perimeter-lighted white dial design It has 12 VDC negative ground It can be adjusted for 24 VDC systems It has dual scale - Metric and Imperial Specifications: Brand: Faria SKU: F12812 UPC: 759266128125 Weight: 0.26 LBS