The Marshall Fuel Pressure Gauge allows the user to accurately measure fuel pressure. The liquid filled design allows precise accuracy while holding the needle steady during engine operation. Proper fuel pressure is critical at wide open throttle to prevent lean conditions. Features an easy to read black face with white numerics. Recommended to be used with the B&M Command Flo Fuel Pressure Modifier or the AEM Fuel Pressure Regulator. A nice upgrade if you are using a non-liquid filled fuel pressure gauge. Does not include fittings. This can also be used as a direct replacement for B&M fuel pressure gauges.