Safe Material:Made of plastic,aquarium clear Automatic Accurate Readable SaltWater Hydrometer.
Durable Clear Acrylic:Accurate, durable, and easy to read your marine aquarium’s salt level and specific gravity,Small and waterproof.if the specific gravity between 1.000 – 1.019,show that the specific gravity is small;if the specific gravity between 1.020 – 1.023,show that the specific gravity is nomal;if the specific gravity between 1.024 – 1.030,show that the specific gravity is big;
Clearly Safe Zone Indicated:Includes solinity and specific grovity scales.The outside rang of scale indicates salinity(PPT).The inside range of scale indicates gravity.And with safe zone clearly indicated.Range of use: 0-40 degrees (1.000-1.030).If the salinity ppt between 32 – 40，show that the salinity hydrometer is high;If the salinity ppt between 27 – 31，show that the salinity hydrometer is normal; If the salinity ppt between 0 – 26，show that the salinity hydrometer is light.

MEASURES ON 2 SCALES – Aquarium Refractometer features specific gravity (D20/20) 1.000-1.070 and parts per thousand 0~100‰ ( 1‰=1 PPT=1000PPM), 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) function, allow you to obtain the accurate result faster and easier