Bench / Fittings / Fitting

Used on: the beer-out side of a ball-lock corny keg, taking an FFL swivel or push-in flare fitting on the MFL tail.

The liquid ball-lock disconnect is usually black and is keyed to the liquid post so it will not seat on the gas post. Its 1/4 MFL tail seals on the flare face, so it takes an FFL swivel or a push-in flare fitting. Keeping gas grey and liquid black is what stops you sending beer up the gas line.

Flare fittings seal on the 45 degree flare face and must never be taped. Push-in fittings seal on an O-ring against the tube wall and need the tube cut square. Barbs seal under a worm clamp. Getting the sealing method right matters more than the thread label, because most homebrew leaks are a taped flare or an unclamped barb.