The internal bore sizes of Buteline Polybutene-1 pipes and corresponding fittings are as below:
| Pipe | Fittings | ||
|---|---|---|---|
| Pipe Size | I.D. of Pipe (mm) | Fittings Size | I.D. of Fittings (mm) |
| 10mm | 6.9 | 10mm | 4.5 |
| 16mm | 12.1 | 16mm | 9.0 |
| 22mm | 17.1 | 22mm | 12.8 |
| 28mm | 22.2 | 28mm | 18.0 |