Description
Gate – QD fitting [Engine Side, 6 mm, US standard] (QDF-US)
This Gate QD (quick-disconnect) fitting is an engine-side fitting for 6mm air line, made to the US standard. It is used on HPA (high pressure air) set-ups to join the air line to the engine or replica, so that the line can be connected and released in a moment without tools.
Gate is a Polish company best known for its airsoft electronics, such as the TITAN and ASTER trigger units, and it also produces components for HPA systems. A good quality quick-disconnect is one of the most useful additions to any HPA rig: it lets you separate your replica from the tank and line for transport, storage or a quick swap between guns, without having to unscrew fittings or bleed the whole system down.
How it works
A quick-disconnect is made of two halves: a male plug and a female coupler. This engine-side fitting sits at the replica end of the system, and mates with the corresponding coupler on your air line. Push the two together and they lock and seal; pull back the collar on the coupler and they come apart. Because QD couplings come in different standards that are not interchangeable, it is important that both halves of the connection are of the same standard, in this case US.
Choosing the right standard
Gate offers this fitting in both EU and US standard versions. Check the coupler already fitted to your air line, or the standard used by the rest of your team if you share tanks and lines, and choose the matching version. Mixing standards will not connect properly and can leak. If you are building a new system from scratch, pick one standard and stick to it across all of your lines and replicas. The EU standard version is also available.
Key features
- Quick-disconnect fitting by Gate
- Engine-side (replica-end) fitting
- For 6mm air line
- US standard coupling
- Fast, tool-free connection and release of the air line
- Makes transport and storage of HPA replicas easier
Compatibility
For HPA systems using 6mm air line, and for use with a US standard quick-disconnect coupler. It will not mate correctly with EU standard couplers. Check the line size and the connection on your engine or replica before ordering, and contact us if you are unsure which fitting you need.
Care and maintenance
Always turn off the regulator and bleed the pressure from the line before disconnecting. Keep the fitting clean and free of grit, and fit a dust cap or keep the line coupled when it is not in use. A tiny amount of a lubricant suitable for HPA O-rings can help seals last longer; avoid petroleum-based products. Inspect the O-rings periodically and replace them if you notice leaks.
Who is it for?
HPA users who want a quick, reliable way to connect and disconnect their air line from their replica, and anyone setting up or standardising a US standard HPA system.
Please note: This listing is for the engine-side fitting only. Always depressurise your system before connecting or disconnecting fittings.

![Gate - QD fitting [Engine side, 6 mm, US Standard] (QDF-US)](https://onlyairsoft.co.uk/wp-content/uploads/2026/10/fdc242ec04854559b2282206df0e384f_84ae1638-7205-438f-b0f6-ae54960fe639.jpg)







