1、Accurate, durable, and easy to read sea water hydrometer 2、This product is designed with an automatic level function, can automatically identify the level to avoid errors 3、Very accurate measurement readings, please rest assured to purchase 4、And each hydrometer has a laser engraved patent number 5、Fit for brackish and marine aquariums. Perfect for testing both salinity and specific gravity of your brackish and marine tanks. Description: Size: 9*12cm Feature: Accurate, durable, and easy to read sea water hydrometer. This product is designed with an automatic level function, can automatically identify the level to avoid errors. Very accurate measurement readings, please rest assured to purchase. And each hydrometer has a laser engraved patent number. Note: Fit for warm water aquarium (20°C -30°C). Temperature changes will cause the reading changes. The accuracy of unit proportion is up to plus or minus 0.001. Package included: 1 x Hydrometer 1 x Stick 1 x Hydrometer 1 x Stick