The DFM 5.1 Doppler flowmeter from Greyline Instruments measures flow from outside a pipe. The clamp-on ultrasonic sensor mounts on any 1/2-inch ID or larger pipe and can be used for wastewater, sludge, slurries, abrasives or any liquid with bubbles or suspended solids. Calibration and startup is simple with a built-in five-button keypad. It has a large backlit display and totalizer, isolated 4-20 mA output and six control relays. Options include a built-in data logger and reporting system with USB output, Windows software, and intrinsically safe sensor. 888/473-9546; www.greyline.com.