SodaStream CO2 cylinder (TR21-4 (often pin-valve)) vs Stout Faucet: specs compared
Updated 05 September 2026.
5
specs differ
SodaStream CO2 cylinder (TR21-4 (often pin-valve)) and Stout Faucet differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.
| Spec | SodaStream CO2 cylinder (TR21-4 (often pin-valve)) | Stout Faucet |
|---|---|---|
| Designation | TR21-4 (often pin-valve) | 7/8"-14 shank mount, restrictor plate |
| Size / thread | TR21 x 4 mm trapezoidal, frequently behind a proprietary quick-connect valve | mounts on a 7/8-14 shank; carries a 5-hole restrictor plate behind the spout |
| Fitting form | soda-maker CO2 cylinder | flow-restricting beer faucet |
| Seals on | O-ring on the valve stem | coupling nut draws the faucet body onto the shank nose; the restrictor plate is internal |
| Rating / role | small refillable soda cylinder brewers repurpose for kegging | the faucet that pours nitro stout, forcing beer through a restrictor disc to break out the nitrogen |
Questions and answers
How do SodaStream CO2 cylinder (TR21-4 (often pin-valve)) and Stout Faucet compare?
SodaStream CO2 cylinder (TR21-4 (often pin-valve)) and Stout Faucet differ on 5 specs: designation, size / thread, fitting form, seals on, rating / role.