CARBO Instruments 1.5" Fuel Pressure Gauge, Reliable And Dampen Pulsation & Vibration To Keep Reading Steady During Engine Operation, Easy To Vent Plug For Accurate Readings. Stainless Steel Case, Glycerin Filled, 1/8" NPT Connection, For Use To Read The Pressure Of Fuel, Oil, Water, Air, Compressor, Hydraulics, Hvac, Gaseous & Liquid Media That Are Not Highly Viscous Or Crystallizing And Not Corrosive Or Oxidizing To Copper Alloy Parts.