Retired products cannot be ordered

This probe currently has an exceptionally long lead time. If you would like to consider an alternative option, please call Instrumart to discuss your application.



  • Range: 0-14 pH
  • Disposable Tefzel and titanium design
  • Platinum ORP electrode
  • ORP: ±1500 mV
  • Maximum Process Pressure: 100 psig
  • Long-life

This product is being phased out and will be obsolete in the near future. The suggested replacements are:

Please contact us if you have any questions.


The Rosemount Analytical Triple-junction Model 385+ is now offered with SMART capabilities. SMART option becomes enabled when used with the Model 1056, 1057 Analyzer and on 6081P wireless transmitter. The pH-loop capabilities include auto-recognition of the SMART sensor, automatic upload of calibration data and associated time stamp, historical recording of pH diagnostics (slope, offset, reference impedance, glass impedance). This trending data allows technicians to predict frequency of maintenance and estimate sensor life for a particular process condition. Additional SMART features include factory calibration, resetting SMART sensor calibration data with user menus without power cycling, and manufacturing information.

The Rosemount Model 385+ Sensor is designed to provide advanced sensor diagnostics available with the Models 54e,1055, 1056 or 1057 pH/ORP Analyzer, or Models 81, 3081, 4081, 5081, 6081 or Xmt Transmitter. (Please refer to the instrument's product data sheet for complete information.) These advanced sensor diagnostics provide preventative maintenance by notifying the operator to replace an aged sensor or clean a fouled sensor for continuous optimum performance.

The Model 385+ Sensor measures the pH or ORP (Oxidation Reduction Potential) of aqueous solutions in pipelines, open tanks, or ponds. It is suitable for applications where a low cost, industrial, disposable sensor is required. The combination electrode features a peripheral ceramic junction. The triple junction reference cell provides longer life in processes containing sugar, ammonia, chlorides, sulfides or other poisoning ions. The Model 385+ body is constructed of molded, chemically resistant Tefzel in two standard body versions.

The retraction version is housed in a titanium tube, with a plug-in style surface mount preamplifier in a weatherproof junction box. It is designed for use with a standard 1-1/2 in. ball valve assembly for process mounting where a separate sample stream is difficult or impossible to provide. The entire installation process is accomplished without line depressurization and minimal process fluid loss. Following sensor removal from the ball valve, maintenance and replacement is easy.

The insertion/submersion version has two body configurations: 25 ft (7.6 m) integral cable and preamplifier; 15 ft (4.5m) integral cable for use with remote preamplifier.

The Model 385+ pH/ORP Sensor: Standard features include a Tefzel sensor body with a triple junction gel filled reference electrode and automatic temperature compensator housed in a titanium tube. The retractable version comes with a weatherproof junction box, a process connector, and preamplifier. The insertion/submersion version has two optional body configurations: integral SMART preamplifier (-03) option. The SMART is standard preamp option. It is offered with 25 ft (7.6 m) integral cable. A conventional Model 385+ is offered with 15 ft (4.5 m) integral cable for use with remote preamplifier if the distance to the instrument exceeds 15ft. The 385+ is designed to be used with the Models 54e,1055, 1056 or 1057 pH/ORP Analyzer, or Models 81, 3081, 4081, 5081, 6081 or Xmt pH/ORP Transmitter.


Required Components

These additional components are required for the operation of your product. We strongly advise you to purchase these components unless you already own them or own a suitable alternative.


Mounting Bracket


Please consider these optional accessories.


This product can be used in the following applications: