CGA-326 nitrous oxide valve: 0.825"-14 NGO right hand, external, large round nipple, cylinder valve outlet nut, round seat, seals on washer against a round nipple seat. What it fits and the adapters to join it to other keg fittings.

Updated 05 September 2026.

Bench / Fittings / Fitting

CGA-326 nitrous oxide valve (0.825"-14 NGO RH, round seat)

Where 0.825"-14 NGO RH, round seat is used, its real dimensions, and how to connect it to other keg fittings.

Published dimensions

Designation: 0.825"-14 NGO RH, round seat
Size / thread: 0.825"-14 NGO right hand, external, large round nipple
Fitting form: cylinder valve outlet nut, round seat
Seals on: washer against a round nipple seat
Rating / role: the nitrous oxide cylinder connection; shares the thread of CGA-320 but not the seat

Used on: nitrous oxide cylinders, sometimes crossed with CO2 kit because the 0.825-14 thread is identical.

CGA-326 uses the same 0.825-14 thread as CGA-320 but a round nipple seat, so a CO2 regulator nut can start on a nitrous valve and then fail to seal or seal on the wrong gas. Nitrous oxide is not a beverage gas, so this is a hazard to avoid, not an adapter to buy: keep CO2 regulators on CO2 (320) tanks.

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

Connect CGA-320 CO2 cylinder valve to CGA-326 nitrous oxide valvenot compatible CGA-320 CO2 cylinder valverelated fitting (0.825"-14 NGO RH)W21.8 CO2 cylinder valverelated fitting (W21.8-14 (DIN 477 / BS 341 No.8))G5/8 regulator inletrelated fitting (G5/8 (BSP parallel))TR21-4 soda cylinder valverelated fitting (TR21x4 (soda / SodaStream-style))CGA-580 nitrogen / beer-gas cylinder valverelated fitting (0.965"-14 NGO RH)SodaStream CO2 cylinderrelated fitting (TR21-4 (often pin-valve))

Questions and answers

What is the designation of the CGA-326 nitrous oxide valve (0.825"-14 NGO RH, round seat)?

0.825"-14 NGO RH, round seat

What is the size / thread of the CGA-326 nitrous oxide valve (0.825"-14 NGO RH, round seat)?

0.825"-14 NGO right hand, external, large round nipple

What is the fitting form of the CGA-326 nitrous oxide valve (0.825"-14 NGO RH, round seat)?

cylinder valve outlet nut, round seat

What is the seals on of the CGA-326 nitrous oxide valve (0.825"-14 NGO RH, round seat)?

washer against a round nipple seat