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YSI™ Model 550A Dissolved Oxygen Meter

Rugged DO Meter designed for the field

Supplier:  YSI™ 550A25

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Catalog No. 13-298-120

Item Discontinued This item has been discontinued by the supplier. Please to view product availability in your area.

Includes: Four C batteries, DO/temperature probe, cable; available with and without carrying case



  • Accurate measurement of dissolved oxygen and temperature simultaneously
  • Waterproof, impact-resistant case
  • Innovative field-replaceable DO electrode with screw-on cap membranes
  • Quick sinking, weighted probe
  • Large easy-to-read backlit display
  • Features calibration in % and mg/L, altitude and temperature compensation, and a low battery indicator

Order Info

Available with 12–, 25–, 50–, and 100 ft. cables. Replacement DO electrode sold separately. Dimensions: 9L x 4 3/4 x 2 1/2 in.H (23 x 12 x 6cm).


CE marked CE compliant


Meets IP67 requirements

Warranty and Services

Three-year warranty on instrument and one-year warranty on replaceable electrode



Meter, DO/temperature probe, 4 C Batteries, Cable
2 lb.
0 to 50mg/L
0 to 500% Air Saturation
23°F to 113°F
C Alkaline
9 in.
23 cm
12 cm
0 to 20mg/L, ±0.3mg/L or 2% of reading, whichever is greater, 20 to 50mg/L, ±6% of reading
DO, Temperature
CE, IP67
0.91 kg
3 Years
0.01, 0.1mg/L
0.1% Air Saturation
2000 hr.
9 x 4.75 in. (23 x 12 cm)
25 ft.
4.75 in.
2.5 in.
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