Features: 1. Insert the hydrometer 15cm below the water until the water overflows the baffle. 2. Specific gravities safety range: 1.020-1.023. 3. Readable accuracy that reaches a maximum of + (-) 0.002 gravities units. 4. Endurable ABS plastics for durable and sturdy use. Specifications: Product Name: Sea Water Hydrometer / Salt Hydrometer Material: Plastics Size: about 19*5cm / 7.5*2.0inch Packing List: 1* Salinity Tester Notes: 1. Duetothelightingeffectsandshootingangles,thereis acolordifferenceintheproduct, pleaseunderstand. 2. Duetomanualmeasurement,thereisatoleranceintheproductsize. See more product details 1.Use with Ease: Insert the hydrometer into the water tank at a depth of more than 15cm (when the insertion line is less than 15 cm, the accuracy of the surfaces of the tank will be affected). 2.Safety Range: Read the specific gravities according to the inner scale and the salinity (PPT) according to the outer scale. The recommended ratio in the tank is 1.020-1.023 (safety range). Please wash with water every time after use. 3.Measuring Precision: The hydrometer is small and waterproof and is designed with clear readable accuracy that reaches a maximum of + (-) 0.002 gravities units. 4.Strong and Durable: Made of dependable ABS materials, the Sea Water Hydrometer performs sturdiness, reliability, and durability, and is able to be used for a long time. 5.Wide Application: The aquarium hydrometers are suitable for measuring salinity in aquariums, fish tanks, ponds, pools, etc., and can be used for the salinity test of seawater. _x000D_ _x000D_