Duotight ball-lock gas QD (8mm): snaps over the gas post; integrated 8mm push-in tail, snap-on gas 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 gas QD (8mm) (grey QD, 8mm push-in tail)
Where grey QD, 8mm push-in tail is used, its real dimensions, and how to connect it to other keg fittings.
Published dimensions
- Designation
- grey QD, 8mm push-in tail
- Size / thread
- snaps over the gas post; integrated 8mm push-in tail
- Fitting form
- snap-on gas QD with integrated push-in
- Seals on
- O-ring over the post shoulder; 8mm push-in O-rings on the tube
- Rating / role
- the gas-side ball-lock disconnect with a built-in 8mm Duotight, no separate flare fitting needed
Used on: the CO2 side of a ball-lock corny keg, taking EVABarrier 8mm line directly with no MFL/FFL step.
This disconnect combines the gas ball-lock body and an 8mm Duotight push-in in one part, so 8mm line pushes straight in with no flare swivel between them. It is keyed to the gas post like any grey gas QD, and often carries a check valve. Buy the 8mm version for 8mm line, the 9.5mm version for 9.5mm 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 gas QD (8mm) (grey QD, 8mm push-in tail)?
grey QD, 8mm push-in tail
What is the size / thread of the Duotight ball-lock gas QD (8mm) (grey QD, 8mm push-in tail)?
snaps over the gas post; integrated 8mm push-in tail
What is the fitting form of the Duotight ball-lock gas QD (8mm) (grey QD, 8mm push-in tail)?
snap-on gas QD with integrated push-in
What is the seals on of the Duotight ball-lock gas QD (8mm) (grey QD, 8mm push-in tail)?
O-ring over the post shoulder; 8mm push-in O-rings on the tube