The PDFM 5.1 employs the latest technology in Doppler signal processing with an improved ability to filter out noise and produce flow measurement accuracy far greater than previously possible. Mount the ultrasonic sensor on the outside of a pipe and this new PDFM 5.1 Portable Doppler Flow Meter shows flow rate instantly. Use it for flow troubleshooting, spot checks or balancing flow. Simply enter pipe diameter with the 5-button keypad and the PDFM 5.1 will display, totalize and data log in your choice of gallons, liters or any engineering units.Features of the PDFM 5.1 include 4-20mA output, 300,000 point data logger with USB output and Windows™ software. There is also a rechargeable NiMH battery that supply power for at least 24 hours continuous use. Plus, the push button sleep mode prolongs battery life, making it suitable for extended periods of operation. Recommended for “difficult liquids” like wastewater, sludge, slurries, chemicals and abrasives.