Features with automatic temperature compensation (ATC) function Designed for testing the concentration of salt water and brine, ideal for aquariums, marine monitoring and quality control in research and clinical laboratories With just a couple of drops of aquarium water you know exactly what the salinity is Measures on 2 scales, specific Gravity (D 20/20) and parts per thousand (�), provides a direct reading of the specific gravity and concentration of salt in water Comes with a hard case, dropper, screwdriver and cleaning cloth