Description:_x000D_ Size: 7.5*19cm_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 1Accurate, durable, and easy to read sea water hydrometer 2This product is designed with an automatic level function, can automatically identify the level to avoid errors 3Very accurate measurement readings, please rest assured to purchase 4And each hydrometer has a laser engraved patent number