Plugs are also known as nipples.
Sockets have a shut-off valve that stops the flow when the coupling is separated, so air won’t leak from the line. They are push-to-connect style. To connect, push the plug into the socket until you hear a click. To disconnect, twist the sleeve on the socket and pull out the plug. This twist-to-disconnect feature reduces the chance of accidental disconnection.
Note: To ensure a correct fit, make sure that the plug and socket have the same coupling size.