Aysix Stebatec LDM: Ultrasonic Multi-Path flow meter for wastewater, raw sewage and rainwater flows. The LDM is a calibrated measuring device for the measurement of the non-reflux flow of wastewater in open channels or canals. 10 flow velocity measuring sections distributed over the entire cross-section provide accurate flow values when the sensor is partially or completely filled. The level measurement is integrated in the housing of the device.