A refractometer is a tool that accurately measures the salinity of your aquarium. Light refracts differently according to the amount of salt that is dissolved in the water and is independent of temperature.

It is designed for the measurement of seawater or low concentration saltwater.
Dual scale: 0-100‰ salinity (parts per thousand) and specific gravity d: 1.000-1.070
Automatic temperature compensation function minimizes the effect of the temperature on testing result.
Easy to Use: It’s very easy to use even for new users. And no battery needed.
Ideal for marine fishkeeping aquarium, saltwater pool, marine monitoring,lab,agricultural, gardening and educational purposes.