Review on Suitable Conditioning Refrigerant Charging Recovery by Mark Dahmer

I'm an HVAC service technician. I started using them a few weeks ago and for the most part they work great. They leak a very small amount of refrigerant when connected to the service port. The only problem I found with them is; If there is pressure at the end of the gauge and it is not connected to the unit, a small amount of refrigerant may leak through the valve. This is a very minor issue and I recommend this valve.