Connecting four-way fittings of different pipe diameters, diverting/combining flow and reducing the diameter at the same time, adapting to changes in the size of the pipe network (e.g. water supply, industrial pipelines).
| NO. | Diameter/mm | Thickness/ mm |
| 1 | 18×15 | 1.5×1.5 |
| 2 | 22×18 | 1.5×1.5 |
| 3 | 28×18 | 1.5×1.5 |
| 4 | 28×22 | 1.5×1.5 |
| 5 | 35×18 | 1.5×1.5 |
| 6 | 35×22 | 1.5×1.5 |
| 7 | 35×28 | 1.5×1.5 |
| 8 | 42×18 | 1.5×1.5 |
| 9 | 42×22 | 1.5×1.5 |
| 10 | 42×28 | 1.5×1.5 |
| 11 | 42×35 | 1.5×1.5 |
| 12 | 54×18 | 1.5×1.5 |
| 13 | 54×22 | 1.5×1.5 |
| 14 | 54×28 | 1.5×1.5 |
| 15 | 54×35 | 1.5×1.5 |
| 16 | 54×42 | 1.5×1.5 |
