Hydro-Dyne Engineering, Inc.
Hydro-Flow Filtration Systems, Inc.
Hydro-Trace Incorporated
Hydrocarb (Trinadad) Limited
Hydrocarbon Filtration Systems Inc.
Hydroflo, Inc.
Hydroflow, Inc.
HydroGeo North America L.L.C.
Hydrokinetics, Inc.
Hydromatix Inc.
Hydrometrics, Inc.
Hydropath Holdings Limited
Hydropress Wallander & Co.
Hydropress Wallander & Co. AB
HydroProcessing, L.L.C.
Hydroprocessing, L.L.C.
HydroProcessing, LLC
Hydroprocessing, LLC
Hydroprojekt
Hydroquip Technologies, Inc.