Weber Sensors, 4320.12M/6, 24 VDC Flow-Captor Type 4320.12 M/6 , In-line Analog display flow switch, Stainless Steel Housing with M12 Connector. Measuring range 0-20 to 0-300 cm/sec in water systems , 6mm diameter. PNP n.c. output. (with no flow). Cable sold separately.