Plastic quick disconnects for pin lock Cornelius-type kegs.
This is a high quality fitting made by CM Becker in Germany.

Red and black quick disconnects are used for the liquid out tank plug.

1/4 inch male flare (MFL) threaded fittings make it easy to connect a variety of hardware pieces and connectors. MFL fittings are more versatile than barbed fitting, but they must be tightened down properly or they can leak.