A 6400-06-06 | 3/8" JIC Male x #6 SAE/ORB Male hydraulic adapter is a type of hydraulic fitting that connects a JIC female fitting to an ORB (O-ring boss) male fitting. The JIC (Joint Industry Council) male fitting has a 37 degree flare on the end, which mates with a JIC female fitting, while the ORB male fitting has an o-ring on the end that creates a seal when tightened into the female ORB fitting.
See Product Specs Below.