ORP meters for easy field measurements.



  • Absolute and relative mV readings
  • User-replaceable electrodes
  • IP67 waterproof housing
  • “Hold” feature locks readings on display
  • 50-set memory (absolute and relative ORP, temp, date and time stamp)
  • Graphic display with on-screen instructions

Handheld ORP Meter Product Description

The EcoSense® ORP15A pen-style handheld ORP meters provide easy-to-use graphic interfaces, simple one-hand operation, memory, and low cost of ownership. The handheld ORP meter measures ORP (absolute and relative mV) and temperature. The handheld ORP meter is designed for quick, accurate results in an economical platform. The handheld ORP meter design is rugged and designed for harsh environments so you no longer have to worry about electrode breakage or clogged junctions.

The ORP15A Handheld ORP Meter is IP67 rated for wet environments. The handheld ORP meter can save up to 50 readings even if the power is lost. The handheld ORP meter also has data hold, auto shut-off, and low battery features. With a one-year handheld ORP meter warranty and six-month electrode warranty, the ORP15A will fit your needs for an easy-to-use mV instrument for food (vegetable washing and sanitizers), swimming pools, wastewater, and aquaculture sampling.

The handheld ORP meter is typically used to determine the oxidizing or reducing potential of a water sample. It is important to use a handheld ORP meter to measure ORP because it indicates possible contamination, especially by industrial wastewater. ORP can be a valuable measurement if the user knows that one component of the sample is primarily responsible for the observed value. For example, excess chlorine in wastewater effluent will result in your handheld ORP meter measuring a large positive ORP value and the presence of hydrogen sulfide will result in a large negative ORP value.

Measuring ORP
ORP stands for oxidation-reduction potential, which is the measurement (in millivolts, or mV) of the oxidizing or reducing tendency of a solution.  Oxidation is the loss of electrons from an atom, molecule, or ion, which may or may not be accompanied by the addition of oxygen.  When a substance is oxidized, its oxidation state increases.  Reduction is the net gain of electrons.  When a substance is reduced, its oxidation state is lowered.  Oxidation and reduction reactions always accompany each other.  Every oxidation and reduction reaction can be characterized by a halfreaction, which provides all of the chemical substances participating in the reaction (many half-reactions are identified in standard chemistry handbooks or other reference materials).  The ORP of the solution depends on the concentrations of the substances participating in the half-reaction.  In order to calculate ORP when concentrations vary, you must use the Nernst equation.  Due to its logarithmic dependence on concentration and its dependence on multiple solution components, ORP is typically not a good method for measuring concentration.  The best use of an ORP is in monitoring and controlling oxidation-reduction reactions.  When an oxidation-reduction reaction occurs, there is usually a large change in the ORP, which overwhelms the factors that make concentration measurements an issue.  This allows you to ensure that an ORP reaction has gone into completion, and thereby control your application appropriately.

Handheld ORP Meter Applications

The ORP15A Handheld ORP Meter is useful for many types of applications including:

  • Pulp Bleaching
  • Bleach Production
  • Water/Wastewater
  • Aquaculture (Ozone)
  • Fruit & Vegetable Washing
  • Cooling Towers
  • Swimming Pools/Spas
  • Metal Finishing
  • Poultry Processing
  • and many more…

Handheld ORP Meter Specifications

ORP Range: -1100 to 1100 mV
Temperature Range: 14.0 to 212 °F (-10 to 100 °C)
ORP Resolution: 1 mV
Temperature Resolution: 0.2 °F (0.1 °C)
ORP Accuracy: 1 mV ±1 LSD
Temperature Accuracy: ±0.6 °F (±0.3 °C)
ATC Probe: Thermistor, 10k? at 25 °C
Offset Range: User input from -999 to +999 mV
Data Memory: Non-volatile; 50 sets (absolute and relative ORP, temperature, date and time stamp); erase all data function
Operation Temperature Range: 32.0 to 122.0 °F (0.0 to 50.0 °C)
IP Rating: 67
Power: Four LR44 button batteries
Battery Life: 200 hours or greater (low battery indicator)
Size: 0.9×7.4×1.8 inch (23x188x46mm)
Weight: 3.7oz (105g)

Handheld ORP Meter Options

ORP15A Handheld ORP Meter (PN# 606ORP15)
Includes ORP electrode, batteries, and instruction manual.


606112 Spare ORP15A Handheld ORP Meter Probe (PN# 606112)

605118 Replacement battery for ORP15A Handheld ORP Meter (PN# 605118)

605129 Case for ORP15A Handheld ORP Meter (PN# 605129)

Handheld ORP Meter Calibration Solution (125 mL) (PN# 061320)
Zobell solution is used for calibrating ORP/Redox instruments.


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