The BD330 is a precise portable dissolved oxygen (DO) meter that measures dissolved oxygen in % and mg/L and temperature in water and is suitable for a wide range of applications, such as educational and aquaculture, as well as water and environmental analysis. It is suitable for monitoring the oxygen levels of lakes, shrimp and fish tanks. This dissolved oxygen meter's field probes use a polarographic electrode with convenient and easy to replace screw-on cap membranes. It features a built-in temperature probe for automatic temperature compensation. A built-in microprocessor stores, calculates, and compensates for all parameters related to DO determinations. The meter calibrates easily in 2 points (at 100% water-saturated air and in 0 oxygen solution) and has Automatic Temperature Compensation which guarantees the highest accuracy. Applications including: Municipal wastewater/sewage treatment; Environmental water testing; Aquaculture/aquariums for measuring oxygen level in fish and shrimp farming; Natural stream purification system; Boilers; Educational in laboratories and schools; Biochemical manufacturing. etc. This dissolved oxygen meter is able to perform either 1 or 2 points calibration. For single point calibration, we recommend that you perform 100% saturation calibration in the air at 100% relative humidity or the air-saturated water. If the 2 points calibration is selected, the zero oxygen solution needs to be used. The meter has four operation modes: MEASUREMENT, MENU, DATA and FREEZE mode. PACKAGE INCLUDED: 1.Dissolved oxygen Meter; 2.Dissolved oxygen probe; 3.Oxygen probe filling electrolyte; 4.One set of zero oxygen reagent; 5.One membrane cap; 6.Plastic toolbox; 7.Instruction manual; 8.4 AAAA alkaline batteries. Dimensions: 90x175x42mm (3.54x6.89x1.65") Weight: 258 grams (9.1 oz.)