1.This refractometer is design according to the principle that different concentrations liquid have different refractive index ,with quick and accurate characteristics 2.Automatic temperate compensation, the temperature of the water sample will not effect the reading 3.High definition eyepiece give your a broader view and make your can read more accurately 4.Aluminum construction heavy-duty and Light weight, small volume, convenient to carry 5.Soft silicone handle provides good touching feeling