Bs341 8 vs Ball-lock liquid disconnect (MFL) (black QD: specs compared
Updated 05 September 2026.
5
specs differ
Bs341 8 and Ball-lock liquid disconnect (MFL) (black QD differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.
| Spec | Bs341 8 | Ball-lock liquid disconnect (MFL) (black QD |
|---|---|---|
| Designation | W21.8 (British designation) | black QD, 1/4" MFL tail |
| Size / thread | 21.8 mm x 14 TPI right hand, external (the W21.8 thread) | snaps over the liquid post; 1/4" MFL (7/16-20 UNF) tail |
| Fitting form | cylinder valve outlet nut, external | snap-on liquid quick disconnect |
| Seals on | captive O-ring or washer in the nut against the valve outlet | O-ring over the post shoulder; flare face at the MFL tail |
| Rating / role | the British Standard 341 designation for the CO2 cylinder outlet used across the UK | the liquid-side ball-lock disconnect, keyed to the liquid post and usually black |
Questions and answers
How do Bs341 8 and Ball-lock liquid disconnect (MFL) (black QD compare?
Bs341 8 and Ball-lock liquid disconnect (MFL) (black QD differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.