|
| | Die Autobahn GmbH des Bundes | Geestland |
| | STRABAG Property and Facility Services GmbH | Hamburg |
| | Rudolf Hensel GmbH | Börnsen |
| | Ed. Züblin AG | Hannover, Braunschweig |
| | assmann gruppe | Dortmund |
| | PPS Pipeline Systems GmbH | Quakenbrück |
| | Ed. Züblin AG | Hannover |
| | Günter Alsdorf GmbH & Co. KG | Neuwied |
| | FingerHaus GmbH | Frankenberg / Eder |
| | Hilti Deutschland AG | Cloppenburg, Vechta, Leer, Meppen, Oldenburg |
| | PPS Pipeline Systems GmbH | Leipzig |
| | Ed. Züblin AG | Stuttgart |
| | PPS Pipeline Systems GmbH | Quakenbrück |
| | STRABAG Rail GmbH | Brandenburg a.d. Havel-Kirchmöser |
| | PPS Pipeline Systems GmbH | Wiesmoor |