Borehole CTDs Ocean Seven 310 BOREHOLE CTD 43mm GROUND WATER MULTI-PARAMETER PROFILER 43mm. Learn more Ocean Seven 308 CTD Logger Very Low Power, Self-recording, UV-Antifouling, Arctic, Antarctica, Brine, Moorings, ROVs, AUVs Learn more Ocean Seven 28 Micro CTD VERY SMALL DIAMETER AND ACCURATE CTD UP TO 28Hz Learn more