ATC Refractometer

It is designed for the measurement of seawater (marine aquaria) or very low concentrated salt solutions.
Ideal for testing and monitoring aquariums,fish tank, saltwater pool,seawater...
Features automatic temperature compensation (ATC) and Dual Scale: Specific Gravity & Salt Percent.
Easy to Use - Just need 2-3 drops of solution, you can get accurate readings. And no battery needed.
Includes: a firm plastic case, a refractometer ,a cleaning cloth, a screw driver, an operating instructions, 3 suction tube.