1. Aerzener Maschinenfabrik GMBH
2. Atlas Copco AB
3. BAUER COMP Holding GmbH
4. Boge Kompressoren
5. Doosan Portable Power Company
6. Elliott Company
7. Frank Technologies Pvt. Ltd.
8. General Electric Company
9. Hanwha Power Systems
10. Hitachi Ltd.
11. Howden Group Ltd.
12. Ingersoll Rand Inc.
13. Kaeser Kompressoren Inc.
14. Kirloskar Pneumatic Company Limited
15. Kobe Steel Ltd.
16. MAN Energy Solutions SE
17. Mitsubishi Heavy Industries
Ltd.
18. Siemens AG
19. Sulzer AG
20. Zhejiang Kaishan Compressor Co. Ltd.