Oakton Instruments, 35643-30, 1000 Series DO Portable DO Meter Kit with Case and Optical DO Probe35643-30 Includes Only:DO 1000 portable meterOptical DO electrodeCarrying caseFeatures:Digital filter improves measurement speed and accuracyClear large-screen LCD with white backlightIP57 waterproof and dust-resistant rated - great for use under harsh environmentsThe addition to the Environmental Express Oakton product line features updates to measuring water quality easier and faster. The larger display is 2.75 in. by 2.0 in. for better viewing angle, and has indicators for battery life, stability, and calibration. It shows both the parameter and temperature measurements at the same time. The meter is a perfect combination of the most advanced electronics technology, sensor technology, and software design all while being the most cost-effective portable electrochemical meter. The microprocessor-based meter features automatic calibration, automatic temperature, salinity compensation, function set-up, self-diagnostics, automatic power-off, and low voltage display.DO 1000 portable meter uses luminescence technology through an optical sensor, which is stable, accurate, and interference-free. With luminescence optical sensors, oxygen is not consumed during measurements, therefore it is not affected by sample and flow rate, providing a stable measurement. The sensor cap is coated with a light-shielding layer and minimizes the impact from external light sources. This reduces a variety of heavy metal ions interfering in the aqueous environment with chemical substances such as H2S and NH4. The easy-to-use sensor requires no electrolytes or membranes, making frequent calibration not required, with an expected service life of up to 8000 hours.