YSI Pro20i Dissolved Oxygen/Temperature


Easy to use, rugged and reliable, the YSI Pro20i provides
everything you need in a handheld instrument for the
measurement of dissolved oxygen (DO). A true field instrument
with IP-67 waterproof, rubber over molded case, military spec
connectors and 1-meter drop tests ensure durability to provide
years of sampling even in the harshest field conditions.

With the Pro20i, accuracy is not compromised for ruggedness.
The Pro20i can easily be calibrated for fast, accurate
measurements you can trust.

• Integral (i.e. built-in) cable with 1- 4- 10-m field cable
• User-replaceable DO sensors
• One Touch Cal allows for easy DO calibrations within 3 seconds
with the press of a button
• Automatic barometric pressure compensation
• Quick response times; T-95 response time in 8 seconds with
standard membrane (fastest response time on the market)
• Stores 50 data sets; no need to write down data
• Large graphic, backlit display and glow in the dark keypad,
visible in any lighting condition
• Display is visible when wearing polarized sunglasses
• A true field instrument with IP-67, impact-resistant, waterproof
case. Waterproof with and without the battery cover.
• Rubber over molded, slip-proof case provides extra durability
• Multiple languages: English, Spanish, French, and German
• Warranty: 3-year instrument, 2-year integral cable, 1-year
polarographic sensors, 6-month galvanic sensor

   Pro20i  System Specifications (Instrument, Probe, and Cable)


    °C, °F


23 to 131°F (-5 to 55°C) 0 to 45°C for DO compensation for mg/L


0.1°F (0.1°C)


±0.6°F (±0.3°C)

  Dissolved            Oxygen

  % Saturation

  % Local


0 to 500%


0.1% or 1% air saturation (user selectable)


0 to 200% air saturation, ±2% of the reading or ±2% air saturation, whichever is greater; 200 to 500% air saturation, ±6% of the reading

   Dissolved           Oxygen




0 to 50 mg/L


0.01 or 0.1 mg/L (user selectable)


0 to 20 mg/L, ±2% of the reading or ±0.2 mg/L, whichever is greater;

20 to 50 mg/L, ±6% of the reading


   mmHg, mbar,     inHg

    psi, kPa


400 to 999.9 mmHg


0.1 mmHg


±5 mmHg within ±5°C temperature range from calibration point

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