KROHNE Inc.: OPTISONIC 6400 portable ultrasonic flowmeter for liquids measures flow velocity, current volumetric flow and a variety of diagnostic values. Users attach the sensor rail to the pipe, plug in the cables to the handheld OPTISONIC 6400, set up a few parameters, and begin reading instantaneous flow results. Results are stored in the integrated memory for data logging. Data can also be transferred via a USB stick to external evaluation systems for further review.