Remove and install the valve core from a 1/4 inch male flare access fitting WITHOUT the loss of refrigerant
BV-CRT - Ball Valve Core Removal Tool
C&D Ball Valve Core Removal Tool (BV-CRT) for use on 1/4" flare access fitting  CD3930.  With 1/4 Flare Access point. It Removes a Valve Core from a 1/4 Male Flare Access Fitting Without the Loss of Refrigerant. Because it has a Ball Valve Inside Rather Than A Stem-Type Valve, This Tool Can Be Closed With Just a Quarter Turn. Made in the USA!