Stack Classic 52mm auxiliary instruments employ proven professional gauge architecture combining digital microprocessor accuracy with an extremely responsive and precise stepper motor needle movement. While your car is in the paddock, going through scrutineering, or on the concours field, it will retain the aesthetics of era correct instrumentation. Under race conditions however, the needle will display and move like a modern performance analogue instrument providing highly responsive and precise engine performance data when you need it most while affording additional safety by isolating hazardous engine fluids from the driver compartment. Stack Instruments Series, Gauge, Boost, Pro Stepper Motor, 52mm, Classic, -30Inhg To +30PSI,Incl T-Fitting STACK INSTRUMENTS