Auto Meter 3531 Sport-Comp Electric Water Temperature Gauge Traditional incandescent lighting illuminates around the perimeter of the dial 12 and 16 volt compatible, well-suited with nearly every street car or race car electrical system Gauge kit includes 1/8 NPT temperature sender, 3/8 and 1/2" NPT adapters, bulb and socket assembly, red and green bulb covers, mounting hardware, and detailed instructions for installation Auto Meters race proven air-core electric instruments provide quick and accurate readings while keeping hazardous fluids outside of the vehicle