The welding connection consists of a union nut, a gasket and a welding sleeve. They are available in carbon steel or stainless steel.

Technical data (in mm)
| Nominal diameter | A | B | C | D | E | F | Opening of the spanner |
| 3/4” | 20.5 | 15 | 23.3 | 30 | 3 | 14 | 30 |
| 1” | 26 | 20 | 30 | 30 | 3 | 15 | 37 |
| 1 1/4” | 32 | 28 | 38.8 | 32 | 4 | 18 | 46 |
| 1 1/2" | 40 | 32.8* | 44.8 | 40* | 4 | 19 | 52 |
| 2” | 48 | 40 | 56 | 32 | 4 | 24 | 66 |
| 2 ½” | 66.2 | 60 | 72 | 50 | 4 | 30 | 80 |
* for CS: B=35mm, D=32mm
The used gasket has a thickness of 2 mm
| Material | |
| Union nut | MS58 |
| Soldering sleeve | Welding sleeve carbon steel(St 37-2) or stainless steel ( W 1.4571) |
| Gasket | Hecker-Centellen WS 3820 |