Allentare Yellow/Blue 40PSI Mechanical Water Pressure GaugeAllentare marine gauges provide an ideal, cost effective solution for new boats or drop-in replacement gauge for older boats. Allentare gauges are designed to work with most commonly found marine senders and wiring harnesses used today.Features:Connection: M4 StudInput Type: MechanicalMounting Hardware: IncludedVoltage: 12VDiameter: 2-1/16"Diameter (Metric): 52mmMax Range Outer Scale: 40 PSI