Duotight ball-lock liquid QD (8mm): snaps over the liquid post; integrated 8mm push-in tail, snap-on liquid QD with integrated push-in, seals on O-ring over the post shoulder; 8mm push-in O-rings on the tube. What it fits and the adapters to join it to other keg fittings.
Updated 05 September 2026.
Duotight ball-lock liquid QD (8mm) (black QD, 8mm push-in tail)
Where black QD, 8mm push-in tail is used, its real dimensions, and how to connect it to other keg fittings.
Published dimensions
- Designation
- black QD, 8mm push-in tail
- Size / thread
- snaps over the liquid post; integrated 8mm push-in tail
- Fitting form
- snap-on liquid QD with integrated push-in
- Seals on
- O-ring over the post shoulder; 8mm push-in O-rings on the tube
- Rating / role
- the liquid-side ball-lock disconnect with a built-in 8mm Duotight
Used on: the beer-out side of a ball-lock corny keg, taking EVABarrier 8mm line directly with no MFL/FFL step.
The liquid version of the integrated Duotight disconnect: it combines a black liquid ball-lock body with an 8mm push-in, so beer line goes straight in with no flare swivel. It is keyed to the liquid post, so it will not seat on the gas post, which keeps beer out of 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.
Connect this fitting
Questions and answers
What is the designation of the Duotight ball-lock liquid QD (8mm) (black QD, 8mm push-in tail)?
black QD, 8mm push-in tail
What is the size / thread of the Duotight ball-lock liquid QD (8mm) (black QD, 8mm push-in tail)?
snaps over the liquid post; integrated 8mm push-in tail
What is the fitting form of the Duotight ball-lock liquid QD (8mm) (black QD, 8mm push-in tail)?
snap-on liquid QD with integrated push-in
What is the seals on of the Duotight ball-lock liquid QD (8mm) (black QD, 8mm push-in tail)?
O-ring over the post shoulder; 8mm push-in O-rings on the tube