* Real time data recorder, save the data into the SD memory card and can be download to the 　Excel, extra software is no need. * Dissolved oxygen range : 0 to 20 mg/L. * Auto temp. compensation, Auto Calibration. * % salt and height value compensation adj.. * The polarographic type oxygen probe with an incorporated temperature sensor. * Probe head with diaphragm set and electrolyte are included. * Record (Max., Min.), Data hold, zero adjust. * RS232/USB computer interface, Patented. * Patent: Taiwan, China, Japan, Germany, USA pending.