Take your pH and ORP measurements outdoors

Our Thermo Scientific Orion portable meters are built rugged and waterproof for dependable performance, anywhere and anytime. Take advantage of one-hand operation and easy portability for any remote application without sacrificing accuracy and the reliability of your measurements. Identify the best match based on your required features, performance specifications, and budget.

Which portable pH and ORP meter is right for you?

 

Premium

Advanced

Basic

  Orion Star A321 pH Portable Meter
(Star A3210 series)
Orion Star A221 pH Portable Meter
(Star A2210 series)
Orion Star A121 pH Portable Meter
(Star A1210 series)
  Premium pH and ORP measurement portable meters Advanced ORP and pH measurement portable meters Basic ORP and pH measurement benchtop meters
  Premium rugged,
easy-to-use
portable field meters
Advanced portable meters, easy-to-use, dependable field meters Basic portable meters, budget-friendly, simplified field meters
Ideal for
applications in:
pH, mV, ORP, and temperature testing, and field applications Advanced pH analysis ideal for outdoor environments and field applications IP67-rated housing for rugged protection in outdoor environments
pH range –2.000 to 20.000 pH –2.000 to 20.000 pH 2.00 to 16.00 pH
pH resolution 0.1. 0.01, 0.001 pH 0.1. 0.01, 0.001 pH 0.1. 0.01 pH
pH relative accuracy ±0.002 pH ±0.002 pH ±0.01 pH
pH calibration points Up to 5 Up to 5 Up to 3
pH calibration editing Yes No No
Range (mV) ±2000.0 mV ±2000.0 mV ±1600.0 mV
Resolution (mV) 0.1 mV 0.1 mV 0.1 mV
Relative accuracy ±0.2 mV or ±0.05% of reading, whichever is greater ±0.2 mV or ±0.05% of reading, whichever is greater ±0.2 mV or ±0.05% of reading, whichever is greater
ORP mode Yes Yes No
Range (temperature) –5.0° to 105.0°C,
22.0° to 221.0°F
–5.0° to 105.0°C,
22.0° to 221.0°F
–5.0° to 105.0°C,
22.0° to 221.0°F
Resolution (temperature) 0.1°C, 0.1°F 0.1°C, 0.1°F 0.1°C, 0.1°F
Accuracy (temperature) ±0.1°C ±0.1°C ±0.1°C
Temperature compensation Automatic or manual Automatic or manual Automatic or manual
Offset calibration 1 point 1 point Yes
Data points 5000 with date and time stamp 1000 with date and time stamp 50
Log function Manual, automatic with AUTO-READ or timed Manual, automatic with AUTO-READ Manual, automatic with AUTO-READ
Inputs pH electrode BNC, reference pin BNC, reference pin BNC
Inputs ATC probe 8 pin mini DIN 8 pin mini DIN 8 pin mini DIN
Outputs RS232, USB RS232, USB ---
Power supply 4 AA batteries: 800 hrs. battery life (included) or optional universal, 100–240 VAC (sold separately) 4 AA batteries: 800 hrs. battery life (included) or optional universal, 100–240 VAC (sold separately) 4 AA batteries: 2,000 hrs. battery life (included) or optional universal, 100–240 VAC (sold separately)
  Enhance your productivity with accessories for your benchtop and portable meters. Meter Accessories ›

Take your measurements indoors with our complete lab offerings

Benchtop
pH Meters

Benchtop pH and ORP meters

Equip your lab with our benchtop pH and ORP (Oxidation-Reduction Potential) meters that provide dependable performance, accuracy, and reproducibility for your application or analysis needs.
 

 

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pH Electrodes
and Probes

pH and ORP electrodes, probes and sensors

Our extensive assortment of quality pH electrodes, sensors, and probes are designed to make your complex measurements routine, reliable, and accurate—in the lab or in the field. They are available in a variety of body materials, body styles, and sample requirements. Find the best electrode for your application.

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Buffers and
Solutions

Buffers and solutions for use with Orion pH and ORP measurement meters

Complete your pH measurement system by selecting the pH buffer or solution that is right for your application. All Thermo Scientific Orion pH lab buffers and solutions are traceable to NIST reference materials.

 

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Orion solutions, standards and buffers portfolio

Using high-quality solutions to calibrate and maintain your sensors is the best way to ensure your data is both accurate and reproducible. Learn more about why high-quality solutions deliver correct measurements every time.  

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Support

Knowledge Base: Certificates of Analysis and SDS for Orion, ROSS, AQUAfast, AquaMate, and AquaSensors products.

Orion Meters Software and Upgrades
Thermo Scientific Orion benchtop and portable meters are designed to help deliver accurate, consistent results, day after day. Boost productivity by upgrading your software today.

Find your software