pH and Electrochemistry

pH and Electrochemistry
Instruments and other methods to measure pH, conductivity, specific ions, dissolved oxygen, and other parameters; may be handheld or benchtop and manual or electronic (analog or digital); includes pH indicator papers, electrodes, and other probes.
pH and electrochemistry meters and related products are used to assess acidity and alkalinity, conductivity, specific ion concentrations, and dissolved oxygen in water, wastewater, and other solutions. Electrochemistry meters may measure a single parameter (like pH) or they may be multiparameter meters, capable of performing a combination of tests (pH plus conductivity, for example).
Electrochemistry meters are used with various probes and electrodes designed for specific purposes or types of solutions. Electrodes with epoxy bodies are useful for testing food, beverages, and other materials where broken glass could be a problem. Other electrodes are made to withstand higher than usual impact; for use with solutions that contain large particulates; and for compatibility with biological buffers.
Electrodes must be carefully stored and maintained for optimal performance. It’s important to select the right storage bottles and electrode filling, cleaning, rinsing, and storage accessories.
Electrochemistry meters also require regular calibration and maintenance. Standard and certified pH buffers as well as conductivity and specific ion standards are available. Other accessories include electrode supports, bulb guards, cables, connectors, and adapters.
Indicator paper and test strips are another simple, portable, and qualitative way to quickly determine pH and other analytes. The paper or strips contain chemical indicators that produce color reactions. A comparison chart (included) helps to interpret the results. Available in various pH ranges, these are sometimes called “litmus” paper.






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Thermo Scientific™ Orion™ Pro Star PI217 Dual Channel pH/Ion Bench Meter
Designed to provide accurate and reliable pH, ORP, ion concentration and temperature analysis, the Thermo Scientific™ Orion™ Pro Star PI217 dual channel bench meter is well suited for laboratories that desire a modern meter with advance performance.

Temperature (Metric) Range | -30.0°C to +130.0°C |
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Memory | Non-volatile |
Advanced ISE Functions | Single known addition, single known subtraction, double known addition, double known subtraction, analyte addition and analyte subtraction |
Resolution (pH) | 0.1, 0.01 or 0.001 pH |
Languages | Chinese, English, French, German, Italian, Japanese, Korean, Portuguese, Spanish |
Measurement Modes | pH,ORP with mV and Temperature,Ion Concentration (ISE) with Temperature |
Range (pH) | -2 to 20 |
Resolution (ISE) | 0.0001 minimum, 1 to 5 digits |
Channels | 2 |
Accuracy (pH) | ±0.002 pH |
Range (ISE) | 0.0001 to 19999 |
Display Type | 7-in. High-resolution Color Graphic LCD |
Resolution (mV) | 0.1 mV |
Data Points | 10,000 with Date and Time Stamp |
Temperature Probe Calibration | 1 or 2 point temperature offset calibration |
Certifications/Compliance | CE, TUV 3-1, FCC Class A |
Inputs | Channel 1: BNC for pH, ORP or ISE, 8-pin MiniDIN for ATC, pin-tip for reference; Channel 2: BNC for pH, ORP or ISE, 8-pin MiniDIN for ATC, pin-tip for reference |
Accuracy (Temperature) | ±0.3°C, ±0.5°F |
Weight (Metric) | 1.00 kg |
Accuracy (mV) | ±0.2 mV or ±0.05% of the reading, whichever is greater |
Accuracy (ISE) | ±0.2 mV or ±0.05% of the reading, whichever is greater |
Warranty | 2 year meter warranty |
Calibration Points (ISE) | Up to 5 |
Isopotential Point | 7.000 pH; 1.000 ion concentration |
AC Adapter | Universal 100-240 V 50/60 Hz power supply with wall plugs for US/Japan, Euro, UK/Singapore, Australia/New Zealand and China outlets |
Log Function Type | Automatic with Auto-Read and Timed Read Modes, Manual with Continuous Read Mode |
Calibration | pH, ORP, Ion Concentration, Temperature |
Calibration Points | 1 to 5 (pH), 1 (ORP), 1 to 5 (ion), 1 to 2 (temperature) |
Alarm Output | Calibration reminder alarm, high and low limit alarm per parameter |
Dimensions (L x W x H) | 218.9 x 153.2 x 91.33 mm; 8.62 x 6.03 x 3.60 in. |
Temperature Selection | Automatic with ATC temperature sensor, ambient or manual |
Keypad | Capacitive touchscreen user interface |
Model | PI217 |
Outputs | USB flash drive, computer or printer (STARA-106) |
Range (Relative mV) | -2000 to 2000 mV |
Calibration Points (pH) | 1 to 5 points |
Backlight Option | Yes |
Weight (English) | 2.20 lbs. |
Resolution (Temperature) | 0.1°C, 0.1°F |
Range (mV) | -2000 to 2000 mV |
Range (ORP) | -2000 to 2000 mV |
Methods | 10 per channel (20 total) |
Thermo Scientific™ Orion™ Pro Star PH211 pH/ORP Bench Meter with Stand
Designed to provide accurate and reliable pH, ORP and temperature analysis, the Thermo Scientific™ Orion™ Pro Star PH211 bench meter is well suited for laboratories that desire a modern meter with advance performance.

Memory | Non-volatile |
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Resolution (pH) | 0.1, 0.01 or 0.001 pH |
Languages | Chinese, English, French, German, Italian, Japanese, Korean, Portuguese, Spanish |
Measurement Modes | pH with mV and Temperature,ORP with mV and Temperature |
Range (pH) | -2 to 20 |
Channels | 1 |
Accuracy (pH) | ±0.002 pH |
Display Type | 7-in. High-resolution Color Graphic LCD |
Resolution (mV) | 0.1 mV |
Data Points | 10,000 with Date and Time Stamp |
Certifications/Compliance | CE, TUV 3-1, FCC Class A |
Temperature Probe Calibration | 1 or 2 point temperature offset calibration |
Inputs | BNC for pH or ORP, 8-pin MiniDIN for ATC, pin-tip for reference |
Accuracy (Temperature) | ±0.3°C, ±0.5°F |
Weight (Metric) | 1.00 kg |
Accuracy (mV) | ±0.2 mV or ±0.05% of the reading, whichever is greater |
Warranty | 2 year meter warranty |
Isopotential Point | 7.000 pH |
AC Adapter | Universal 100-240 V 50/60 Hz power supply with wall plugs for US/Japan, Euro, UK/Singapore, Australia/New Zealand and China outlets |
Log Function Type | Automatic with Auto-Read and Timed Read Modes, Manual with Continuous Read Mode |
Calibration | pH, ORP, Temperature |
Calibration Points | 1 to 5 (pH), 1 (ORP), 1 to 2 (Temperature) |
Alarm Output | Calibration reminder alarm, high and low limit alarm per parameter |
Dimensions (L x W x H) | 218.9 x 153.2 x 91.33 mm; 8.62 x 6.03 x 3.60 in. |
IP Rating | IP54 |
Temperature Selection | Automatic with ATC temperature sensor, ambient or manual |
Keypad | Capacitive touchscreen user interface |
Model | PH211 |
Outputs | USB flash drive, computer or printer (STARA-106) |
Range (Relative mV) | -2000 to 2000 mV |
Backlight Option | Yes |
Temperature Range (English) | -22°F to +266°F |
Calibration Points (pH) | 1 to 5 points |
Weight (English) | 2.20 lbs. |
Resolution (Temperature) | 0.1°C, 0.1°F |
Temperature Range (Metric) | -30°C to +130°C |
Range (mV) | -2000 to 2000 mV |
Methods | 10 |
Range (ORP) | -2000 to 2000 mV |
Thermo Scientific™ Orion™ Pro Star PC215 pH/ion and Conductivity Bench Meter with Stand
Designed to provide accurate and reliable pH, ORP, ion concentration, conductivity, TDS, salinity, resistivity and temperature analysis, the Thermo Scientific™ Orion™ Pro Star PC215 bench meter is well suited for laboratories that desire a modern meter with advance performance.

Salinity Measurement Modes | Natural Seawater (ppt), Practical Salinity Units (PSU), or % NaCl |
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Range (Resistivity) | 1.0 Ω to 100.0 MΩ |
Memory | Non-volatile |
Advanced ISE Functions | Single known addition, single known subtraction, double known addition, double known subtraction, analyte addition and analyte subtraction |
Resolution (pH) | 0.1, 0.01 or 0.001 pH |
Languages | Chinese, English, French, German, Italian, Japanese, Korean, Portuguese, Spanish |
Resolution (ISE) | 0.0001 minimum, 1 to 5 digits |
Display Type | 7-in. High-resolution Color Graphic LCD |
Resolution (mV) | 0.1 mV |
Resolution (Ion) | 0.0001 minimum, 1 to 5 digits |
Data Points | 10,000 with Date and Time Stamp |
Temperature Probe Calibration | 1 or 2 point temperature offset calibration |
Certifications/Compliance | CE, TUV 3-1, FCC Class A |
Accuracy (mV) | ±0.2 mV or ±0.05% of the reading, whichever is greater |
Accuracy (ISE) | ±0.2 mV or ±0.05% of the reading, whichever is greater |
Warranty | 2 year meter warranty |
Temperature Accuracy | ±0.3°C, ±0.5°F |
Calibration Points (ISE) | Up to 5 |
Resolution (Conductivity) | 0.001 μS/cm minimum, auto-ranging, up to 4 digits |
Range (Conductivity) | 0.010 μS/cm to 3000 mS/cm |
Log Function Type | Automatic with Auto-Read and Timed Read Modes, Manual with Continuous Read Mode |
Dimensions (L x W x H) | 218.9 x 153.2 x 91.33 mm; 8.62 x 6.03 x 3.60 in. |
Accuracy (TDS) | ±0.5% reading |
Temperature Selection | Automatic with ATC temperature sensor, ambient or manual |
Keypad | Capacitive touchscreen user interface |
Outputs | USB flash drive, computer or printer (STARA-106) |
Temperature Range (English) | -22.0°F to +266.0°F |
Range (Relative mV) | -2000 to 2000 mV |
Calibration Points (pH) | 1 to 5 points |
Backlight Option | Yes |
Range (mV) | -2000 to 2000 mV |
Range (ORP) | -2000 to 2000 mV |
Methods | 10 per channel (20 total) |
Cell Constant | 0.100 cm-1, 0.475 cm-1, 0.550 cm-1, 1.000 cm-1, 10.00 cm-1 or user-defined from 0.001 to 199.9 cm-1 |
Temperature (Metric) Reference | 5, 10, 15, 20, 25 or 30°C |
Range (pH) | -2 to 20 |
TDS Factor Range | Linear (0.01 to 10.00), ISO/EN 27888, 442, NaCl |
Channels | 2 |
Accuracy (pH) | ±0.002 pH |
Range (ISE) | 0.0001 to 19999 |
Range (Salinity) | 0.010 to 80.00 ppt; 0.01 to 42.00 PSU; or 0.01 to 400.0% NaCl |
Temperature Compensation | Linear (0.00 to 10.00 %/°C), nLFn (non-linear natural water), nLFu (non-linear ultra-pure water), EP/USP or off |
Accuracy (Salinity) | ±0.5% reading |
Resolution (Salinity) | 0.001 ppt minimum; 0.01 PSU minimum; or 0.01% NaCl minimum, auto-ranging |
Accuracy (Conductivity) | ±0.5% reading |
Inputs | Channel 1: BNC for pH, ORP or ISE, 8-pin MiniDIN for ATC, pin-tip for reference; Channel 2: 8-pin MiniDIN for conductivity with ATC |
Weight (Metric) | 1.00 kg |
Resolution (ORP) | 0.1 mV |
Calibration Points (Conductivity) | 1 to 5 points |
Resolution (Resistivity) | 0.1 Ω minimum, auto-ranging |
Isopotential Point | 7.000 pH; 1.000 ion concentration |
Accuracy (Resistivity) | ±0.5% reading |
AC Adapter | Universal 100-240 V 50/60 Hz power supply with wall plugs for US/Japan, Euro, UK/Singapore, Australia/New Zealand and China outlets |
Range (TDS) | 0.010 ppm to 500.0 ppt (TDS factor of 1.00); or 0.010 mg/L to 500.0 g/L (TDS factor of 1.00) |
Resolution (TDS) | 0.001 ppm or mg/L minimum, auto-ranging, up to 4 digits |
Calibration | pH, ORP, Ion Concentration, Conductivity, TDS, Salinity, Temperature |
Accuracy (ORP) | ±0.2 mV or ±0.05% of the reading, whichever is greater |
Calibration Points | 1 to 5 (pH), 1 (ORP), 1 to 5 (ion), 1 to 5 (conductivity), 1 to 5 (TDS), 1 (salinity), 1 to 2 (temperature) |
Alarm Output | Calibration reminder alarm, high and low limit alarm per parameter |
IP Rating | IP54 |
Weight (English) | 2.20 lbs. |
Range (Ion) | 0.0001 to 19999 |
Temperature Range (Metric) | -30.0°C to +130.0°C |
Temperature Resolution | 0.1°C, 0.1°F |
Thermo Scientific™ Orion™ Double Junction Semi-Micro Stem Glass Bodied Combination pH Electrode
Top-performance, semi-micro pH electrodes to measure samples as small as 0.2 mL.

Thermo Scientific™ Orion™ ROSS Ultra™ Refillable Epoxy Bodied pH/ATC Triode™
Accurately measure pH and temperature together in just one electrode, with a built-in temperature sensor.

Type | pH/ATC Combination Electrode |
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Warranty | 2 Years |
Length (Metric) | 120 mm |
Precision | 0.01 |
Isopotential Point | 7 |
pH Range | 0 to 14 |
Diameter (Metric) | 12 mm |
Filling Solution Type | ROSS electrode 3 M KCl fill solution (Cat. No. 810007) |
Material | Epoxy Body |
Junction | Glass Fiber |
pH Relative Accuracy | 0.03 pH for buffers using automatic temperature compensation |
Temperature (Metric) Operating | 0°C to 100°C |
Internal Reference | ROSS |
Thermo Scientific™ Orion™ AquaPro™ Double Junction Combination pH Electrodes
Measure the pH of viscous liquid samples quickly, and accurately, with clog-resistant Orion™ AquaPro™ pH electrodes.

Length (Metric) Cable | 1 m |
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Temperature (English) Operating | 32°F to 140°F |
pH Range | 0 to 14 |
Length (English) Cable | 39 in. |
Junction | Open |
Storage Requirements | Always store in pH storage solution, Orion 910001. Either store in a beaker of storage solution or reassemble in the storage bottle the electrode was provided with. |
pH Relative Accuracy | ±0.02 |
Temperature (Metric) Operating | 0°C to 60°C |
Internal Reference | Ag/AgCl Double Junction |
Thermo Scientific™ Orion Star™ A321 pH Portable Meter
Accurately monitor pH, mV, ORP and temperature with our waterproof, portable pH meter for high performance in challenging field locations.

Memory | Non-volatile memory preserves data log, calibration log and meter settings |
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Resolution (pH) | 0.1/0.01/0.001 |
Languages | English, Spanish, French, Italian, German and Chinese; Portuguese and Korean available with software update |
Measurement Modes | pH,mV,Relative mV,ORP with Temperature |
Range (pH) | -2 to 20 |
Channels | 1 |
Accuracy (pH) | ±0.002 |
Power Supply | 4 AA batteries (included) or universal AC adapter (sold separately) |
Data Management Details | Transfer single, range or all data points to printer or computer |
Battery Life | 800 hr. |
Display Type | LCD Graphic, Backlit |
Resolution (mV) | 0.1mV |
Data Points | 5000 with Date and Time Stamp |
Temperature Probe Calibration | 1 point temperature offset calibration |
Certifications/Compliance | CE, TUV 3-1, FCC Class A |
Inputs | BNC (pH or ORP electrode), pin-tip (reference electrode), 8 pin MiniDIN (ATC temperature probe) |
Weight (Metric) | 0.5 kg |
Accuracy (mV) | ±0.2 mV or ±0.05% of reading whichever is greater |
Warranty | 3 Year Meter |
Temperature Accuracy | ±0.1°C |
Stability | Selectable fast, medium, slow or Smart Stability setting; Selectable off or Automatic Smart averaging setting |
Temperature (English) Operating | 41°F to 113°F (ambient) |
Isopotential Point | 7.000pH |
AC Adapter | Universal 50-60 Hz, 100-240 VAC power adapter (sold separately, Cat. No. 1010003) |
Log Function Type | Automatic data logging with Auto-Read and Timed measure modes; manual data logging with Continuous m |
Calibration | pH with calibration editing option, relative mV (RmV), ORP and temperature |
Battery Type | 4 x AA |
Relative Humidity Range | 5 to 85%, non-condensing |
Calibration Points | 1 to 5 |
Alarm Output | High/low limit alarm, calibration due alarm |
Dimensions (L x W x H) | 24cm x 10cm x 6.5cm (9.5 in. x 3.9 in. x 2.6 in.) |
Temperature Selection | Manual or automatic with ATC temperature probe |
IP Rating | IP67 |
Keypad | Comprehensive with menu-specific function keys and dual purpose scroll/shortcut keys |
Model | Orion Star A321 pH/mV/RmV/ORP/Temperature Portable Meter |
Outputs | USB, RS-232 |
Temperature Range (English) | 22.0°F to 221.0° F |
Range (Relative mV) | ±2000.0 mV |
Backlight Option | Yes (Selectable) |
Weight (English) | 1.2 lb. |
Temperature (Metric) Operating | 5°C to 45°C (ambient) |
Temperature Range (Metric) | -5.0°C to +105.0°C |
Range (mV) | ±2000.0 mV |
Range (ORP) | ±2000.0 mV |
Methods | 10 per channel with password protection |
Temperature Resolution | 0.1°C, 0.1°F |
Thermo Scientific™ Orion™ ROSS™ Sure-Flow™ Epoxy Bodied Combination pH Electrode
Attain stable, drift-free measurements of challenging samples using a sure-flow electrode with its unique free-flowing liquid-to-liquid junction.

Includes | Detachable bulb guard, 2 x 60mL bottles of fill solution |
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Length (Metric) Cable | 1 m |
Temperature (English) Operating | 32°F to 212°F |
Precision | 0.01 |
pH Range | 0 to 14 |
Diameter (Metric) Cap | 16 mm |
Length (English) Cable | 39 in. |
Filling Solution Type | 3M KCl |
Material | Epoxy Body |
Junction | Sure-Flow |
Temperature (Metric) Operating | 0°C to 100°C |
Internal Reference | ROSS |
Thermo Scientific™ Orion™ 2-Cell Conductivity Electrodes
Achieve accurate measurements from ultrapure water, sea water, and more with these versatile 2-cell conductivity electrodes, available in a variety of materials and measurement ranges.

Type | 2-Electrode Conductivity Cells |
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Thermo Scientific™ Orion™ Temperature Probes
Automatically correct pH measurements for variation in electrode slope due to temperature change.

Temperature (English) Operating | 32°F to 212°F |
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Storage Requirements | Store in air |
Temperature (Metric) Operating | 0°C to 100°C |
Thermo Scientific™ Orion™ Chloride Ion Selective Electrodes
Easily and reliably analyze free chloride ions in aqueous solutions. Provides quick, accurate and economical measurements.

Type | Combination ISE |
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For Use With (Equipment) | Chloride electrodes can be used on any ISE meter with a BNC connection The electrodes can also be used on meters with a variety of inputs when an adapter cable is used. |
Thermo Scientific™ Orion™ Dissolved Oxygen/BOD Probe
Make any pH meter a dissolved oxygen meter with this dissolved oxygen/BOD probe.

Dissolved Oxygen (Concentration Range) | 0 to 14 ppm |
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For Use With (Equipment) | Dissolved Oxygen/BOD Probe |
Sensor Types | Polarographic Dissolved Oxygen Sensor |
Temperature (Metric) Operating | 15°C to 35°C |
Thermo Scientific™ Orion™ Epoxy Bodied Temperature Probes
Get fast, accurate measurements in lab or field with this ATC Probe, which automatically corrects pH measurements for variation in electrode slope.

Diameter (English) Body | 0.2 in. |
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Type | ATC Probe |
Accuracy | ±1°C |
Length (Metric) | 120 mm |
Temperature (English) Operating | 32°F to 176°F |
pH Range | 0 to 14 |
Length (English) | 4.7 in. |
Material | Epoxy |
Diameter (Metric) Body | 6 mm |
Temperature (Metric) Operating | 0°C to 80°C |
Fisherbrand™ accumet™ Basic AB330 Benchtop Laboratory Conductivity Meter
Ideal for daily conductivity, TDS and salinity testing of your routine laboratory samples, the accumet™ Basic AB330 Benchtop Meter provides essential functions needed without complicated functions at a budget-friendly price.
Memory | Non-volatile |
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Cell Constant | 0.1 to 10 |
Measurement Modes | Conductivity with Temperature,TDS with Temperature,Salinity with Temperature |
Temperature (Metric) Reference | 15, 20, 25 or 30°C |
Temperature Coefficient | 0 to 10 %/°C |
TDS Factor Range | 0.4 to 1 |
Range (Salinity) | 0 to 80 ppt |
Data Management Details | Printed or CSV Format |
Temperature Compensation | Linear |
Display Type | 5 in. LCD |
Accuracy (Salinity) | ±1% Full Scale |
Resolution (Salinity) | 0.01, 0.1 ppt |
Voltage | 100/240 V |
Accuracy (Conductivity) | ±1% Full Scale |
Data Points | 500 |
Inputs | Conductivity, ATC |
Accuracy (Temperature) | ±0.3°C (±0.5°F) |
Calibration Points (Conductivity) | 84 μS, 1413 μS, 12.88 mS, 111.8 mS |
Stability | Indicator Icons |
Warranty | 3 Years |
Resolution (Conductivity) | 0.01, 0.1, 1 μS; 0.01, 0.1 mS |
Range (Conductivity) | 0 μS to 500 mS |
AC Adapter | Universal Power Adapter |
Resolution (TDS) | 0.01, 0.1, 1 ppm; 0.01, 0.1 ppt |
Calibration | Conductivity, TDS, Salinity, Temperature |
Calibration Points | 1 to 5 (Conductivity), 1 to 5 (TDS), 1 (Salinity), 1 (Temperature) |
Accuracy (TDS) | ±1% Full Scale |
IP Rating | IP54 |
Data Logging | Automatic with Auto-read and Timed Modes, Manual with Continuous Mode |
Model | AB330 |
Outputs | Port for Computer or Printer |
Frequency | 50/60 Hz |
Backlight Option | Yes |
Resolution (Temperature) | 0.1°C (0.1°F) |
Temperature Range (Metric) | -5°C to +105°C |
Fisherbrand™ accumet™ XL250 Benchtop pH/ISE Dual Channel Meters
Provide advanced pH and ion measurements with simple operation and offer a large, vivid color touch-screen display. Fisherbrand accumet XL250 pH/ISE dual channel benchtop meters offer advanced features with simple operation to help ensure your measurements are reliable and your laboratory processes are efficient.
Length (Metric) | 24.6 cm |
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Detection Range | Multiple |
Length (English) | 9.68 in. |
Resolution (pH) | 0.1/0.01/0.001 |
Range (pH) | -2 to 20 |
Width (Metric) | 17.3 cm |
Resolution (ISE) | 2/3/4 Digits |
Accuracy (pH) | ±0.002 |
Range (ISE) | ±2000 mV |
Accuracy | Multiple |
Data Management Details | 3 to 86400 sec. |
Display Type | LCD |
Voltage | 100/240 V |
Resolution (mV) | 0.1mV |
Data Points | 2000 |
Certifications/Compliance | NIST, ISO, FDA, USDA, EPA |
Inputs | 2 BNC, 2 ATC |
Weight (Metric) | 1.13 kg |
Height (English) | 3.89 in. |
Height (Metric) | 9.9 cm |
Accuracy (mV) | ±0.2 mV |
Accuracy (ISE) | 0.5% full scale (monovalent ion), 1% full scale (divalent ion) |
Warranty | 3 Years |
Temperature Accuracy | ±0.3°C |
Calibration Points (ISE) | 2 to 6 |
Dimensions (L x W x H) | 24.6 x 17.3 x 9.9cm (9.7 x 6.8 x 3.9 in.) |
Outputs | RS232, USB-A, Mini-B USB, RJ45, stirrer port (2) |
Frequency | 50/60Hz |
Calibration Points (pH) | Up to 6 preset or 5 custom |
Weight (English) | 2.5 lb. |
Range (mV) | ±2000 mV |
Temperature Resolution | 0.1°C |
Resolution | Multiple |