Ball-lock quick disconnect (ball-lock QD vs Tailpiece: specs compared
Updated 05 September 2026.
5
specs differ
Ball-lock quick disconnect (ball-lock QD and Tailpiece differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.
| Spec | Ball-lock quick disconnect (ball-lock QD | Tailpiece |
|---|---|---|
| Designation | ball-lock QD, MFL or barb tail | 7/8"-14 nut, 1/4" or 3/16" barb |
| Size / thread | snaps over the corny post; tail is 1/4" MFL (7/16-20 UNF) or a 1/4"/5/16" barb | 7/8"-14 shoulder held by a beer nut; 1/4" or 3/16" hose barb |
| Fitting form | snap-on quick disconnect | barbed nipple with a shouldered nut seat |
| Seals on | O-ring seals over the post shoulder; the tail seals by flare or clamp | flat washer against the shank end under the beer nut; barb under a worm clamp on the hose |
| Rating / role | the universal ball-lock keg connector; gas and liquid are keyed differently | the piece that turns a shank thread into a hose barb for vinyl beer line |
Questions and answers
How do Ball-lock quick disconnect (ball-lock QD and Tailpiece compare?
Ball-lock quick disconnect (ball-lock QD and Tailpiece differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.