Aeromotive - Fuel Pressure Meter (0-15 PSI)1.5" Diameter1/8″ NPT Male Connection0-15 PSI Pressure RangeLiquid Filled For DurabilityIntegral Equalizer Valve Ensures Accuracy Regardless of Operating TemperatureLiquid Filled Gauges offer a better looking, more durable option for gauges that will live in a harsh environment like under the hood, attached to a high-performance engine.  The problem with regular liquid-filled gauges is they can be temperature sensitive, with fuel pressure readings prone to rising and falling with the temperature of the oil in the gauge case, regardless of actual fuel pressure.  As under-hood and therefore gauge temperatures can swing across a large range, this can be especially frustrating. Aeromotive Liquid Filled Gauges feature a custom equalizer valve that allows gauge case to be quickly equalized to the atmosphere, instantly correcting the gauge reading regardless of operating temperature. This product is not legal for sale or use on emission-controlled vehicles except when used as a direct replacement part matching OEM specifications.