Bsp58 vs Ball-lock gas disconnect (MFL: specs compared
Updated 05 September 2026.
5
specs differ
Bsp58 and Ball-lock gas disconnect (MFL differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.
| Spec | Bsp58 | Ball-lock gas disconnect (MFL |
|---|---|---|
| Designation | 5/8" BSP (7/8"-14 nut) | grey QD, 1/4" MFL tail |
| Size / thread | 5/8" BSP female, carried on a 7/8"-14 coupling nut | snaps over the gas post; 1/4" MFL (7/16-20 UNF) tail, often with an integrated check valve |
| Fitting form | parallel beer thread | snap-on gas quick disconnect |
| Seals on | flat nylon or fibre washer on the face of the thread | O-ring over the post shoulder; flare face at the MFL tail |
| Rating / role | the US and UK draft shank and Sanke coupler beer thread | the gas-side ball-lock disconnect, keyed to the gas post and usually grey or white |
Questions and answers
How do Bsp58 and Ball-lock gas disconnect (MFL compare?
Bsp58 and Ball-lock gas disconnect (MFL differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.