The WalkLAB Dissolved Oxygen Meter is designed for full portability. This economical meter is most suitable for use at sea level and for fresh water. It comes with a standard 1 meter probe. An optional 3 or 5 meter probe can be purchased or ordered on request. The specially designed strap-on, hang over bag is fully equipped with all accessories needed to operate the meter. Each unit comes with an extra membrane, a bottle electrolyte and with a salinity conversion table for quick conversion. This basic DO meter is most popular with aquaculture users due to its simplicity. Advanced Features: Utilization of microcontroller technology provides fast, accurate readings allowing digital repeatability Fast In-Air calibration. Uses durable long lasting components including a light weight chemical resistant HDPP casing Large and easy to read Liquid Crystal Display