The Greyline DFM 5.0 doppler flowmeter measures flow from outside a pipe ?-in. ID or larger. It is designed for difficult liquids like wastewater, sludge, slurries, abrasives or any liquid with bubbles or suspended solids. It includes strap-on sensor, backlit display, totalizer, isolated 4-20mA output and two control relays. A built-in datalogger is optional.