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YSI 550A Dissolved Oxygen Meter with 25 Foot Cable

YSI 550A Dissolved Oxygen Meter
with 25 Foot Cable
$ 35 $ 100 $ 300

Looking for a rugged, field-worthy instrument for measuring dissolved oxygen? The new YSI 550A DO instrument features a waterproof (IP-67), impact-resistant case, 25 foot cable and innovative field-replaceable DO electrode modules. Measure dissolved oxygen and temperature simultaneously using YSI's proven polarographic technology for oxygen and YSI Temperature Precision thermistors, the planetwide standard for accuracy. Our new PE membranes provide faster response times with less stirring dependence - saving time with every reading!

Measurements are fast and easy with one-hand operation, an easy-to-use backlit display, low-battery indicator, automatic push-button calibration, and a weighted, quick-sinking probe. The YSI 550A DO has a built-in calibration chamber, direct salinity, temperature, and altitude compensation. The instrument provides simultaneous readings of oxygen and temperature. DO readings include our expanded range of 0-50 mg/L.



  • Field-replaceable DO electrode modules
  • Faster response time
  • Waterproof and meets IP-67 specifications
  • The YSI 556 now comes with the new PE membranes for faster response times and lower stirring dependence.
  • Three-year warranty on the instrument; one-year on the DO module
  • Screw-on cap membranes
  • Over 2000 hours battery life
  • Calibrate in either mg/L or % saturation
  • User-selectable temperature units (Celsius or Fahrenheit)
  • 25 foot cable length
  • Manual salinity input from 0 to 70 ppt