Vacuum Purge and Coolant Refill: Connect the Venturi tool to a compatible air compressor to evacuate trapped air, check the system under vacuum, and draw in fresh coolant. This pneumatic process helps simplify cooling system maintenance without manual air bleeding. Monitor Vacuum and Check for Leaks: The protected gauge provides a clear 0 to -30 inHg reading. After evacuation, close the valve and monitor the gauge; a loss of vacuum may indicate a loose connection or a possible cooling system leak that should be inspected before refilling. Switch Functions Without Removing the Adapter: Once the selected adapter is secured in the radiator or coolant reservoir opening, it can remain in place while switching from vacuum evacuation to coolant filling, reducing repeated connections during service. Five Adapters for Medium and Small Vehicles: Includes four round adapters measuring 1.38, 1.54, 1.73, and 2.17 in. (35, 39, 44, and 55 mm), plus one flexible conical adapter for additional opening sizes. Suitable for many cars, crossovers, SUVs, vans, and other light-duty vehicles; verify opening size before ordering. Complete Air Fitting and Sealing Set: Includes a vacuum generator with gauge, Venturi adapter with American air fitting, European and Japanese air fittings, filling hose, exhaust hose, 9 O-rings, sealing tape, 2 hose clamps, and a pair of protective gloves. An air compressor is required and is not included.