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 metersAdvanced ORP and pH measurement portable metersBasic ORP and pH measurement benchtop meters
 Premium rugged,
easy-to-use
portable field meters
Advanced portable meters, easy-to-use, dependable field metersBasic portable meters, budget-friendly, simplified field meters
Ideal for
applications in:
pH, mV, ORP, and temperature testing, and field applicationsAdvanced pH analysis ideal for outdoor environments and field applicationsIP67-rated housing for rugged protection in outdoor environments
pH range–2.000 to 20.000 pH–2.000 to 20.000 pH2.00 to 16.00 pH
pH resolution0.1. 0.01, 0.001 pH0.1. 0.01, 0.001 pH0.1. 0.01 pH
pH relative accuracy±0.002 pH±0.002 pH±0.01 pH
pH calibration pointsUp to 5Up to 5Up to 3
pH calibration editingYesNoNo
Range (mV)±2000.0 mV±2000.0 mV±1600.0 mV
Resolution (mV)0.1 mV0.1 mV0.1 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 modeYesYesNo
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°F0.1°C, 0.1°F0.1°C, 0.1°F
Accuracy (temperature)±0.1°C±0.1°C±0.1°C
Temperature compensationAutomatic or manualAutomatic or manualAutomatic or manual
Offset calibration1 point1 pointYes
Data points5000 with date and time stamp1000 with date and time stamp50
Log functionManual, automatic with AUTO-READ or timedManual, automatic with AUTO-READManual, automatic with AUTO-READ
Inputs pH electrodeBNC, reference pinBNC, reference pinBNC
Inputs ATC probe8 pin mini DIN8 pin mini DIN8 pin mini DIN
OutputsRS232, USBRS232, USB---
Power supply4 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.
 

pH Electrodes
and Probes

pH and ORP electrodes, probes and sensors

Our extensive assortment of quality pH electrodes, sensors, and probes are available in a variety of body materials, body styles, and sample requirements. 

Buffers and
Solutions

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

We offer a variety of NIST traceable pH buffer solutions, pH electrode storage solutions, electrode cleaning solutions, lab buffer kits, and electrode filling solutions for every application.

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