I originally connected this to my car's AC system by connecting it to Schrader test ports with connectors that are pressurized when plugged in. Even if the plug is removed, the Schrader valve remains open while the plug is removed, often resulting in freon and oil splattering all over the car and person. These connectors connect to the test port without using a Schrader valve. After connecting the plug, the Schrader valve is turned on by turning the knob on the plug. Required for connection toโฆ