... Sea, River, Lake, and Port and Waterway Dredging Hydrological Survey on hydr D330 is the Single Beam echo sounder ... -screen, easy to operate· The minimum measuring ability is only 0.3m. Technical Parameters SpecificationWorking Frequency: 200KHzTransmitting Angle ... Environment: -30~60Dimensions: 34cmX30cmX15cmWeight: 8.5Kg*I/O Port: Keyboard and Mouse Ports, Printer Port, two RS232 Ports, two USB Ports, ...