Constant Oil Pressure, Reached Shortly After Starting The Engine, Is The Sign Of An Engine In Good Condition. This Instrument Can Be Used To Monitor Oil Pressure After Starting And While The Engine Is Running. It Will Warn You If The Oil Needs Topping Up Or If There Is A Problem With The Engine. The 553 Series' Increased Performance And Accuracy Is Achieved By Its Original Equipment-Type Electric Aircore Meter Movement Or Solid Brass Mechanical Bourdon Tube Meter Movement. All Feature Back-Lit™ Illumination And Include Easy-To-Read Mounting Instructions.