digital psi bar turbo boost vacuum gauge with install kit t-fitting : mechanical, electronic, supercharger
The boost gauge monitors the pressure in the turbo or supercharger. As the engine thrust increases, the turbocharger or supercharger will push for greater boost. However, more is not always better, only to a certain extent is good. Within a safe pressure range, the car will perform well, or it may cause engine failure. The boost gauge showing the pressure of the turbo, so you can let off some gas and make some adjustments when approaching the dangerous range.