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Do you need help obtaining accurate and reliable water quality analysis measurements? 

The Ohaus Starter Pen Meter ST20M-B offers a seamless solution. Perfect for laboratory and field applications, this compact device ensures precise readings of pH, conductivity, TDS, and more, catering to professionals who demand efficiency and accuracy. Its user-friendly features make the Starter Pen Meter an indispensable tool for any water analysis task, allowing you to focus on results rather than process complications.

Key Benefits:

  • Versatile Measurement Capabilities: Accurately measures pH, ORP, conductivity, salinity, TDS, and temperature, making it a multifunctional instrument for comprehensive water analysis.
  • High Accuracy: Ensures precise readings with an accuracy of ±0.05 pH and ±2.0% F.S., enhancing the reliability of your data.
  • Durable Construction: Equipped with a robust ABS housing and IP67 waterproof rating, it is designed to withstand challenging environments, ensuring longevity and durability.
  • Portable and Convenient: Lightweight and compact design with a protective sensor cap and wrist strap for secure handling and easy transport.
  • Energy Efficient: Features an automatic shut-off function to preserve battery life, making it ideal for extended field use.
  • 5-Year Warranty: Enjoy peace of mind and long-term reliability with a comprehensive 5-year warranty on your investment.

Investing in the Ohaus Starter Pen Meter ST20M-B will transform your approach to water quality testing. Imagine the peace of mind that comes with consistent, accurate measurements and the efficiency of having a reliable tool at your fingertips. Perfect for environmental scientists, lab technicians, and quality control professionals, this meter from Liberty Scales simplifies complex measurements and empowers you to deliver outstanding results. Feel confident and proficient with every test – that’s the promise of Ohaus, now extended to the realm of laboratory instruments with the Starter Pen Meters.

Reach out to our dedicated team for further information and personalized assistance. Call us at (661) 888-1919 or email us at We're here to help you every step of the way!


  • Meter Type: TDS; Conductivity; pH

  • Measurement Range: 0.0 – 1000 mg/L; 0.0 – 99.0 °C; 0.00 – 14 pH; 0 – 1999 μs/cm

  • Accuracy: ±2.0 % F.S.; ± 0.05 pH / ± 0.5 °C

  • Measurement Resolution: 1μs/cm; 0.01 pH

  • Display: LCD

  • ATC: Yes

  • Temperature compensation: Not Applicable

  • Automatic Shutdown: Yes, After 6 minutes of non-use

  • Battery Life: 100 Hours with Disposable Batteries

  • Calibration: 3 Point

  • Conductivity accuracy (±): 2 %

  • Conductivity measuring range: 0 – 1999 µS/cm

  • Dimensions: 1.5 in x 7.28 in x 1.77 in (38 mm x 185 mm x 45 mm) (LxHxW)

  • Net Weight: 3.88 oz (110 g)

  • Number of Buttons: 3

  • pH accuracy (±): 0.05

  • pH measuring range: 0 – 14

  • Power: 4 AG13 Batteries (Included)

  • Protection Rating: IP67

  • Temperature Display: Yes

  • Temperature Sensor: 50 KΩ NTC

  • Working Environment: 50°F – 104°F, 85%RH, non-condensing (10°C – 40°C, 85% RH, non-condensing)

  • Wrist Strap: Yes
  • Free Shipping: Available across 48 continental USA. Extra charges may apply for residential, farm, or rural areas.
  • Express Shipping: Overnight and faster shipping options available at additional costs. Quotes obtainable via email.
  • Delivery Time: Typically 5 to 7 business days, varying by location and external conditions.
  • Tracking Information: Provided via email upon shipment. Accessible through account login. Additional information available upon request.
  • Return Policy: 15-day return period for unused, original condition products. A 25% restocking fee applies. Buyer covers original and return shipping costs.
  • Customer Support: Contact at (661) 888-1919 or for queries or concerns about shipping.