1. Caterpillar Inc.
2. Cummins Inc.
3. Generac Holdings Inc.
4. Kohler Power Systems Inc.
5. Yanmar Co. Ltd.
6. Atlas Copco AB
7. W?rtsil? Oyj
8. Briggs & Stratton Corporation
9. Honda Motor Co. Ltd.
10. Mitsubishi Heavy Industries
Ltd.