Salinity Refractometer - 0 to 28%Measures salt content in sea water, pickling brines and other applications. While the scale is calibrated for sodium chloride, it can also be used for calcium chloride, barium cobalt, magnesium, cesium, potassium, sodium chloride, cupric sulfate, potassium iodide, citric acid, acetic acid and (vinegar). Place a drop or two of a sample on the prism and read the results. Sper Scientific portable refractometers work in ambient light with no battery or