PINPOINT Salinity Meter Kit will accurately and immediately measure the amount of salt in any marine or freshwater system and displays a digital reading. The reading is fully temperature compensated, which is difficult or impossible with nearly any commercial hydrometer. The conversion chart will precisely show the corresponding density (specific gravity) or % salt (refractometer) values. This monitor is especially useful to determine the low level of salt required for Koi, whether in an aquarium or outdoor pond. Comes complete with meter, probe and calibration fluid. The PINPOINT Salinity Meter and accessories fit perfectly into the PINPOINT Armor Hard Carry Case (also available on Amazon) for safe storage.