Features: 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. Specification: Description:_x000D_ Size: 9*12cm_x000D_ _x000D_ Feature:_x000D_ _x000D_ Accurate, durable, and easy to read sea water hydrometer. _x000D_ This product is designed with an automatic level function, can automatically identify the level to avoid errors. _x000D_ Very accurate measurement readings, please rest assured to purchase. _x000D_ And each hydrometer has a laser engraved patent number. _x000D_ _x000D_ Note: _x000D_ Fit for warm water aquarium (20C -30C)._x000D_ Temperature changes will cause the reading changes._x000D_ The accuracy of unit proportion is up to plus or minus 0.001._x000D_ _x000D_ Package included:_x000D_ 1 x Hydrometer_x000D_ _x000D_ 1 x Stick PackageList: 1 x Hydrometer 1 x Stick