Anchoring security for cruising sailors! Find deep water easily from your tender. We have imported this unique, Japanese-made portable sonar depth sounder for more than 10 years. It is very accurate and since it floats, its high visibility case makes it easy to find if dropped overboard. In addition to recreational use by boaters, scuba divers and ice fishermen, it is commonly used by coastal surveyors, bridge maintenance workers and scientists. By changing the end caps, you can have two Depthmates in one! To convert SM-5 to SM-5A with external transducer, purchase the EC-5A cap plus transducer (see Accessories).