• SMART enabled
  • Available in hemi bulb, flat bulb, HF resistant, and Hi pH glass
  • Special features for processes with low conductivity, hydrofluoric acid, high pH, and reference poisoning elements
  • Watertight VP8 multiple-pin connector available which eliminates cable twisting.
  • Double or triple junction reference cell
  • Various mounting options
  • Sealed Tefzel body provides maximum protection


The Rosemount Analytical models 399 and 399VP are general purpose pH/ORP sensors. These sensors are compatible with nearly all Rosemount Analytical pH/ORP analyzers. These sensors include a SMART option that becomes enabled when used with the Model 1056 and 1057 analyzers.

The Rosemount Analytical models 399 and 399VP are housed in a molded Tefzel body with Viton o-rings, making each sensor virtually indestructible and chemically resistant. The simplified construction, designed with user convenience in mind does not require electrolyte replenishment or any high maintenance troubleshooting procedures. The 399 features an integral cable design while the 399VP is offered with a watertight Variopol VP multiple pin sensor-to-cable connector which eliminates re-wiring and cable twisting when replacing sensors. Installation is easily achieved through the wide variety of mounting configurations. Both Models feature 1 inch (MNPT) front and rear facing connections for insertion, submersion, or flow-through pH and ORP applications.

Both the 399 and 399VP are provided with a double junction reference which protects the reference element from harsh elements. When large amounts of harsh elements are present, an optional triple junction is available to help prolong the sensor life.


This product can be used in the following applications: