Used to connect different interfaces (e.g. threaded and smooth pipe) to realize pipe specification conversion and sealing.
| NO. | Diameter/mm | Thickness/ mm |
| 1 | 15×1/2" | 1.5 |
| 2 | 18×1/2" | 1.5 |
| 3 | 18×3/4" | 1.5 |
| 4 | 22×1/2" | 1.5 |
| 5 | 22×3/4" | 1.5 |
| 6 | 28×1 | 1.5 |
| 7 | 35×11/4" | 1.5 |
| 8 | 42×11/2" | 1.5 |
| 9 | 54×2 | 1.5 |
