Tr21 vs Beernut: specs compared
Updated 05 September 2026.
5
specs differ
Tr21 and Beernut differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.
| Spec | Tr21 | Beernut |
|---|---|---|
| Designation | TR21x4 (soda / SodaStream-style) | 7/8"-14 (1" hex) |
| Size / thread | TR21 x 4 mm pitch trapezoidal | 7/8"-14 straight thread, 1 inch hex across flats |
| Fitting form | trapezoidal cylinder valve, external | internally threaded hex coupling nut |
| Seals on | O-ring on the valve stem | compresses a rubber washer between the tailpiece and the shank end |
| Rating / role | small refillable soda-maker CO2 cylinders | the US beer industry standard nut that secures a tailpiece to the back of a shank |
Questions and answers
How do Tr21 and Beernut compare?
Tr21 and Beernut differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.