"The OBS-3+ Turbidity Monitor is a submersible probe, part of our OBS® line of products that use a backscatter method to measure turbidity. The OBS-3+ operates in the range of 0 to 4000 NTU. It replaces the OBS3 on our price lists.","The OBS-3+ can be used in several applications, ranging from water quality in freshwater rivers and streams to sediment transport and dredge monitoring. The output for the OBS-3+ can be specified at time of order, allowing you to customize the sensor to match the datalogger being used to make the measurement."