The OBS-5+ monitors high sediment concentrations using an infrared laser and a proprietary dual photo-detection system (U.S. Patent No. 5,796,481). The probe transmits sediment concentration and depth to a PC via an RS-232 or RS-485 link. Data are also stored internally. The OBS-5+ is ideal for monitoring dredging and site-remediation operations, determining dredge efficiency, providing data for sediment transport research, and supporting undersea mining and trenching. (OBS® is a registered trademark of Campbell Scientific.)