Note: The OBS-3+ is scheduled to be discontinued 31-December-2019.  The OBS-3+ is a submersible turbidity probe that has sideways-facing optics. It uses OBS technology to measure suspended solids and turbidity for applications ranging from water quality in freshwater rivers and streams to sediment transport and dredge monitoring. Campbell Scientific data loggers measure the OBS-3+ probe's output and calculate turbidity.