Post Firestone vs GAS Checkvalve: specs compared
Updated 05 September 2026.
5
specs differ
Post Firestone and GAS Checkvalve differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.
| Spec | Post Firestone | GAS Checkvalve |
|---|---|---|
| Designation | 9/16"-18 UNF | 1/4" FFL x 1/4" MFL |
| Size / thread | 9/16"-18 UNF (about 14.3 mm major) | 1/4" FFL (7/16-20 UNF) inlet and 1/4" MFL (7/16-20 UNF) outlet, or barb ends |
| Fitting form | UNF male post thread | one-way flare check valve |
| Seals on | poppet inside the post; post base O-ring seals to the keg lid | flare faces at each flare end; barb under a clamp on barb versions |
| Rating / role | gas and liquid posts share the thread; disconnect snaps over the outside | passes CO2 toward the keg and blocks beer or foam from returning up the gas line |
Questions and answers
How do Post Firestone and GAS Checkvalve compare?
Post Firestone and GAS Checkvalve differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.