Hallocool Salinity Refractometer features dual scales: Specific Gravity 1.000 to 1.070 (D 20/20) and 0-100PPT, which allow to get the both results at just one testing. Automatic temperature compensation (ATC) function, allow you get the accurate readings consistently, no need to control the liquids temperature deliberately, just make the sample temperature at room temp. This brine refractometer is very easy to use, just put 2-3 drops on the prism of the refractometer, towards light source, then you get the accurate reading. The refractometer designed for measuring saltwater, seawater and salinity of water, ideal for aquarium monitoring, marine fishing keeping, agricultural and educational purposes. Seawater refractometer is made of aluminum and rubber materials, durable, anti-rust and wear-resistant Package Includes: 1 x Salinity refractometer 1 x Mini screwdriver 1 x Plastic pipette 1 x English manual 1 x Plastic storage box 1 x Cleaning cloth (random color)