Professional Automatic Temperature Compensation Salinity Refractometer for Aquariums, Marine Monitoring, Saltwater Testing...Dual Sacle: 0-100ppt & 1.000-1.070 Specific Gravity

Brand new Salinity Refractometer that is used to measure the salinity levels of saltwater aquariums and the worlds oceans. Calibrate with either distilled water or a 35ppt Salinity standard. Wipe off the saltwater after each use. This unit comes with Automatic Temperature Compensation or "ATC". This feature allows you to get a reading outdoors when the temp is between 50'F-86" (10'C-30'C). If you test outside of temp range your readings will become gradually more and more inaccurate. For best results, test indoors. No batteries necessary as you only need strong light - daylight (sunny or cloudy) or a lamp/flashlight.