Review on XtremepowerUS Adjustable Coupler Connector Adapter by William Hunter

I've only used this set once on my hose set but it worked great and was even easier to use than my previous quick connect adapters. Check valves are a great feature to make connecting and disconnecting fittings easier. These adapters consist of two functional parts. The first is the automatic shut off when they are removed from the high and low pressure fittings, allowing you to maintain pressure on your gauge set. The second is "valve" in the adapter. While not actually a valve, turning the dial doesn't actually shut off flow. It's basically just an actuator that activates a schrader valve on your pressure ports. In the closed position, the pin retracts so the Schrader valve will not activate when the adapter is connected or disconnected. But when you turn the valve to the "open" position, the pin falls into the Schrader valve, opening the valve and effectively connecting the two systems. (This is why some people say the valve is mislabeled. Because it rotates in an illogical direction to open and close. But it works correctly.) You leave the valves closed when you get out of the car. This means that there is no refrigerant/oil loss when connecting to the high and low pressure connections. Once secured you can open the valves to activate the Schrader valves and actually connect the car to a set of sensors. Then when you're done testing, adding refrigerant, etc., close the valves that separate the two systems. And then there is virtually no loss of refrigerant when the adapters are disconnected. A very practical adapter set that makes the job easier and cleaner.