Salinity Refractometer for Aquarium Seawater Marine Fishkeeping Salinity Tester 0-100PPT & 1.000-1.070 Salinity Hydrometer Slatwater Refractometer with Automatic Temperature Compensation (ATC)Brand: Hallocool Features: MEASURES ON 2 SCALES Aquarium Refractometer features specific gravity (D20 20) 1. 000 1. 070 and parts per thousand 0~100 , allow to get two results in different units by one test WIDELY USE Salinity Refractometer measures saltwater, salinity of water or seawater, ideal for aquariums, marine monitoring, fish keeping, and saltwater pools ATC FUNCTION Saltwater refractometer with automatic temperature compensation (ATC)