Starting at $738.00 Starting at $701.10



  • Dissolved Oxygen (% saturation)
    • Range: 0 to 500% air saturation
    • Accuracy: up to ±2% of the reading
  • Dissolved Oxygen (mg/L)
    • Range: 0 to 50 mg/L
    • Accuracy: up to ±2% of the reading
  • Temperature
    • Range: -5 to 55°C
    • Accuracy: ± 0.3°C
  • Barometer
    • Range: 400 to 999.9 mmHg
    • Accuracy: ±5 mm Hg
  • Internal barometer for highest accuracy
  • Choose Polarographic or Galvanic field sensors or lab BOD
  • Seven kits available as options
  • One Touch Cal calibrates within 3 seconds with the push of a button
  • Stores 50 data sets
  • IP-67, impact-resistant, waterproof case


The YSI Pro20 Dissolved Oxygen Meter provides everything needed in a handheld dissolved oxygen meter. It is a rugged, reliable instrument that is easy to operate while featuring user-replaceable sensors and cables as well as the convenient One Touch Cal feature which makes the Pro20 extremely user friendly.

The Pro20 is a true field instrument. Meeting IP-67 specifications while using military spec connectors and a rubber over-molded case, the YSI Pro20 Dissolved Oxygen Meter is designed for the toughest conditions.

Choose from 7 Pro20 kits. Kits include everything from lab to field (or both) along with DO probe choices. Available sensors are EPA approved for wastewater compliance reporting of BOD, CBOD, and DO.

Readings are shown on a graphic, backlit display. The YSI Pro20 Dissolved Oxygen Meter also records and stores up to 50 data sets. Dissolved oxygen readings can be either percent saturation (with a range from 0 to 500%) or mg/L (with a range of 0 to 50mg/L). Accuracies of up to ±2% are reached by incorporating an internal barometer. Fast response times with the Polarographic or Galvanic sensor allows you to complete your sampling routine quickly. The long life of the Polarographic sensor saves time and money and reduces your overall cost. The Galvanic sensor enables you to start sampling immediately without a warm-up period. Either sensor you choose for the field will give you accurate, quality data.

The YSI Pro20 Dissolved Oxygen Meter does not include the cable and sensor which must be purchased separately.


Here's how some of our customers use this product...

Monitoring Dissolved Oxygen in Wine Making

The Background: Our customer is a vineyard that needs to test for dissolved oxygen at various stages in the winemaking process.

The Problem: High levels of dissolved oxygen can promote the growth of bacteria. Though the bacteria can be controlled with sulphur dioxide, vintners want to use as little of that as possible as it can affect the quality of the wine.

The Solution: We recommend the YSI Pro20 Dissolved Oxygen Meter. The Pro20 is a simple and rugged instrument which is perfectly suited for this application as it can utilize the membrane style DO probes. The classic membrane style of measuring dissolved oxygen in liquids will not be negatively affected by the alcohol content in the wine while the newer optical style probes will degrade. In addition to a drop in style probe, for larger volumes, YSI also offers a BOD style probe that can be mounted right to the top of a wine bottle.

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