One-hand simple operation with automatic temperature compensation and calibration to air makes this pen meter excellent for environmental field work. Allows students to determine water quality for a variety of real-life applications such as general environmental testing, labs, industrial and municipal testing, aquariums, fish hatcheries, and much more. Features include: • A range of 0–20.0 mg/L; 0–100% • A resolution of 0.1 mg/L; 0.1% • An accuracy of ±0.4 mg/L; ±0.7% • A temperature range of 32–122 • Simultaneous display of dissolved oxygen and temperature readings • Ability to hold readings and recall min/max Polarographic probe has a built-in temperature sensor and easy to replace pop-off probe heads. Meter is IP-67 waterproof and comes ready to use in a soft carrying case with a belt loop, two spare probe heads, electrolyte, and 4 AAA batteries. 8" x 2" x 1½".