CO₂ cylinder fittings vary by country. This page helps you quickly determine whether your local CO₂ cylinder can be used with the FIZZIQ system—and if so, whether it’s a direct fit or requires a simple in-country stem and nut swap.

Most customers can confirm compatibility in under a minute by checking where their cylinder is filled and how the valve is marked. When in doubt, our support team can help.

Our regulators are manufactured with a ¼″ NPT right-hand inlet port. Compatibility depends on whether your local CO₂ cylinder connector can terminate in ¼″ NPT RH.

Fast answer: CGA-320 is typically direct-fit in North America. Many other countries work with a local nut + stem if (and only if) the regulator-side stem thread is ¼″ NPT RH.

60-Second Compatibility Check

Step 1 — Where is your CO₂ cylinder filled/exchanged?

  • If you refill/exchange in USA / Canada / Mexico, you likely have CGA-320 (direct fit).
  • If not, continue to Step 2.

Step 2 — Look for markings on the valve

Common markings include:

  • CGA-320, DIN 477, BS 341
  • W21.8, W21.7, W22, JIS
  • Type 30, G5/8

Step 3 — If there are no markings, measure the thread OD

  • ~21 mm (0.83") → often CGA-320 family
  • ~21.8 mm (0.86") → often W21.8 × 1/14 family (DIN/BS family)
  • ~22 mm → often JIS/Korea family
  • ~27 mm / G5/8 → BSP family (often not plug-and-play)

What the result means

DIRECT FIT CGA-320 (0.825″-14 NGO, RH)
  • No adaptor and no stem swap required.
CONDITIONAL Supported with a local nut + stem
  • Common cylinder families: W21.8 × 1/14 (often labeled DIN 477 No.6 / BS 341 No.8), W21.7 × 1/14 (France/Spain/Italy family), W22 × 14 (JIS/Korea), AU/NZ Type 30.
  • UK & Ireland note: BS 341 No. 8 is also commonly referred to as “No. 30” in the trade; these names describe the same CO₂ valve thread.
  • Your local nut+stem must have ¼″ NPT right-hand male threads on the regulator side.
  • If the local stem is not ¼″ NPT RH, it will not fit our regulator body.
NOT SUPPORTED Do not force adaptors
  • If your local connector uses left-hand threads, or the stem-to-regulator interface is not ¼″ NPT RH, our regulator cannot be safely adapted.
  • In that case, we recommend using a locally sourced regulator designed for your region.

Note: Gas outlet standards exist to prevent dangerous cross-connections. Generic adaptors can defeat that safety intent.

Need help? Send this to Support

  • Country where the cylinder is filled/exchanged
  • Supplier (e.g., Linde / Air Liquide / local brand)
  • Photo of the valve (straight-on)
  • Photo of the valve (side view — shows sealing face)
  • Any stamped markings
  • Measured thread OD in mm (and pitch if available)
Email support@appliedfizzics.com

FAQ

Why is ¼″ NPT (right-hand) mentioned so often?
Our regulator body has a fixed inlet: ¼″ NPT RH. The “local nut+stem” approach only works when the local stem terminates in ¼″ NPT RH on the regulator side.
Can I buy an adaptor online?
We do not recommend generic adaptors. Gas outlet standards are designed to prevent unsafe cross-connections. The safer approach is the correct local nut+stem, or a local regulator designed for your region.
My valve looks like W21.8 × 1/14 — is that DIN or BS?
Many customers see the same physical thread described under different standard names. The safe path is: match the cylinder-side standard correctly, then confirm the stem’s regulator-side thread is ¼″ NPT RH.
My supplier says “No. 30” — I don’t see that listed.
In the UK and Ireland, “No. 30” is a common trade name for the same CO₂ fitting currently designated BS 341 No. 8.

© Applied Fizzics Inc. — International CO₂ Cylinder Compatibility