YSI 51B Dissolved Oxygen Meter accurately measures dissolved oxygen and temperature in water and wastewater. Its Clark-type membrane-covered polarographic sensors with built-in thermistors provide reliable readings. Automatic temperature compensation ensures precise oxygen measurements, while manual adjustments allow for changes in water temperature, salinity, and altitude. The meter's user-friendly interface and clear display make it easy to operate. Its long battery life of approximately 1000 hours ensures uninterrupted use.