651347 REFRACTOMETER SEAWATER, SPECIFICGRAVITY DIGITAL PAL07S
Designed to measure the salinity specific gravity of a solution of seawater and water only.    
Fully digital, surprisingly compact size (pocket size) allows you to easily carry it around and use it outdoors or inside factories.  Features  *Just 2-3 drops of sample  *Easy and quick measuring 
*Measurement displayed in just 3 seconds  *Hot or cold samples can be measured.  *ATC - measurements are shown as if measured at 20°C  *Zero setting (calibration) can be done with distilled or tap water!  *Class IP65 - Dust-tight and Protected against water jets. Rinse clean under running water.