Review on Boltigen Coupler，R1234YF Charging Connector Air Conditioning by Ronald Bleimeyer

Excellent adapter. Allows working on new r1234 systems with r134 hardware. In my case I needed to replace the AC condenser so I switched back to r134 instead of the much more expensive r1234 refrigerant. R 134 is compatible with newer 1234 oils so there are no shifting issues. There is also no need to change the hole.