These connect directly. EVABarrier 6.3mm ID x 9.5mm OD line mates with John Guest 3/8" push-fit without an adapter. Sealing method, the real-world trap, and the exact part to buy.
Updated 05 September 2026.
Connect EVABarrier 6.3mm ID x 9.5mm OD line to John Guest 3/8" push-fit
How to join 6.3 mm ID / 9.5 mm OD and 3/8" (9.5 mm) OD, and what stops it leaking.
These connect directly. EVABarrier 6.3mm ID x 9.5mm OD line mates with John Guest 3/8" push-fit without an adapter.
The two ends
- End A
- EVABarrier 6.3mm ID x 9.5mm OD line (6.3 mm ID / 9.5 mm OD)
- End B
- John Guest 3/8" push-fit (3/8" (9.5 mm) OD)
- A seals on
- the 9.5mm OD is what a Duotight 9.5mm or John Guest 3/8 collet grips
- B seals on
- single O-ring plus stainless collet grab-ring
- Part needed
- none, direct fit
EVABarrier 6.3mm ID x 9.5mm OD line takes a John Guest 3/8 collet as well as a Duotight 9.5mm, since both grip the nominally 3/8 (9.53mm) outer wall. This is the UK do-everything beer line size.
9.5mm and 9.53mm are close enough to cross over on a short run, but specified in different units. On a long warm beer run standardise on one system rather than alternating Duotight and John Guest fittings down the line.
Related connections
Questions and answers
Connect EVABarrier 6.3mm ID x 9.5mm OD line to John Guest 3/8" push-fit?
These connect directly. EVABarrier 6.3mm ID x 9.5mm OD line mates with John Guest 3/8" push-fit without an adapter.