The portable (battery-powered) Doppler PDFM-III ultrasonic sensor mounts on any metal or plastic pipe 1-in.-diameter or larger. A built-in, three-key calibration system permits a choice of engineering units. Standard features include a 10-digit programmable totalizer and a 4-to 20-mA output and RS-232C serial connector. A PC software utilities disk is also included with each flowmeter to receive, display, and store data transmitted. The unit runs for at least 24 hours continuously and can be recharged in five hours (or optionally powered) by a 120- or 220-VAC or a 12-VDC power supply. The PDFM-III is recommended for viscous liquids, slurries, chemicals, and wastewater. Sensitivity is adjustable.