VacuumMate Allweather is the industry standard for fast & accurate synchronizing of up to 4 x carburetor / fuel injection throttle valves on 2 and 4-stroke engines. VacuumMate displays the individual manifold pressure of 4 separate carburetors (or fuel injection throttle bodies) on four vertically arranged bright LED bars (40 LEDs per bar) visible in sunlight. making it ideal even for on-board marine & external use.