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Thermo Scientific™ Orion Star™ A121 pH Portable Meter

Take simple pH and temperature measurements with the Thermo Scientific™ Orion™ Star A121 pH Portable Meter with easy operation for basic field testing

Manufacturer:  Thermo Scientific™ ORISTARA1210

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Catalog No. 13-645-504



Take simple, routine pH, mV and temperature measurements with the Thermo Scientific™ Orion™ Star A121 pH Portable Meter, an easy-to-use and budget-friendly instrument for basic pH analysis in the field. Perform up to a three point pH calibration with easy recall of calibration points and slope. Quickly navigate setup menus and ensure consistent calibrations using the simple keypad layout and on-screen text prompts. This waterproof meter has an IP67-rated housing for rugged protection in outdoor environments.

Thermo Scientific Orion Star A121 pH Portable Meters combine simplicity with accuracy. A large LCD displays pH or mV readings along with temperature. Icons provide quick updates on battery life, electrode status and calibration information. Simple button layout and onscreen messages help with calibration and setup menu choices.
  • Large, informative screen clearly shows the main information, including pH or mV reading, temperature in °C or °F, meter mode, calibration information and battery life
  • Don't miss a reading — AUTOREAD™ locks in the stable reading on your screen and ready indicator alerts when readings are stable
  • Up to three point pH calibration
  • Automatic recognition of USA/NIST™ and DIN buffers
  • Easily recall calibration slope data for procedure checks
  • Nonvolatile memory holds up to 50 data points
  • Four AA batteries (included) provide over 2000 hours of operation or purchase the universal power adapter (sold separately) to run meter on AC power
  • Perfectly portable, waterproof and protected to take anywhere with a IP67-rated housing
  • Three year meter replacement warranty


41° to 113°F (ambient)
0.1°C, 0.1°F
1 point temperature offset calibration
-5.0° to 105.0° C
2 lb.
4 x AA
1 to 3
Orion Star A121 pH portable meter
0.1, 0.01
Star A121 pH meter, 4 AA batteries, literature CD, printed quick start guide and meter test certificate
BNC (pH or ORP electrode), 8 pin MiniDIN (ATC temperature probe)
Simple with highlighted measure key, scroll and shortcut keys
Non-volatile memory preserves log and settings
Orion Star A121 pH/mV/RmV/Temperature Portable Meter
pH electrode, ORP electrode, ATC temperature probe (purchase separately)
Automatic data logging with Auto-Read measure mode; manual data logging with Continuous measure mode
Smart Stability and Smart Averaging
22.0° to 221.0° F
5° to 45°C (ambient)
3 year meter warranty
Manual or automatic with ATC temperature probe
Universal 50-60 Hz, 100-240 VAC power adapter (sold separately, Cat. No. 1010003)
±0.2 mV or ±0.05% of reading whichever is greater
2000 hr.
pH, relative mV (RmV) and temperature
Internal data point memory
CE, TUV 3-1, FCC Class A
24cm x 10cm x 6.5cm (9.5 in. x 3.9 in. x 2.6 in.)
-2.00 to 16.00
Orion Star A121 pH portable meter
pH, mV or relative mV (RmV) with temperature
Universal AC adapter (included) or 4 AA batteries (sold separately)
5 to 85%, non-condensing
±1600.0 mV