HDU 15/25 filters are inexpensive offline filter units with pump capacities from 0.75 to 2.5 litres/minute (0.2 to 0.6 gpm), ideal for small hydraulic power packs, gear boxes (for instance on Wind Turbines), tap changers and injection moulding machines.

Quote from the case study:
Hydraulic System reached ISO 4406 Class 13/12/10 (NAS 1638 Class 4).