1000/400/500 Series MIL-C-4109 Industrial Interchange Air Swing Coupling, Female Half With Safety Vent, -04 Coupling, 3/8-18 Male NPT

Safe automatic venting of trapped air happens during disconnection before the halves fully separate. That means pressure bleeds off in a controlled way rather than the line releasing all at once. It is a built-in feature of the swing coupling design, not something you have to manage manually.