Digital Dissolved Oxygen Meter Lutron PDO-519 is perfect for measuring DO, oxygen in air, and temperature in water. It uses a polarographic probe with a built-in temperature sensor for accurate readings. With a range up to 20 mg/L and ±4 mg/L accuracy, this Dissolved Oxygen Meter features Max/Min display, data hold, and battery operation—ideal for field or lab use. Applications: Agriculture, Fish hatcheries, Laboratory, Aquarium, Medical research, Water conditioning,Quality control, Mining industry, Schools & Colleges.