| 851 MC | 5/2 pneumatic pilot, spring return |
| 851 CC | 5/2 double pneumatic pilot |
| 851 CCD | 5/2 double pneumatic pilot, with differential |
| 851 CFP | 5/2 pneumatic pilot, pneumatic spring return |
| 8513C CC | 5/3 closed centres, double pneumatic pilot |
| 8513A CC | 5/3 open centres, double pneumatic pilot |