Analog Refractometer, Range 0 Percent to 28 Percent NaCI, Automatic Temperature Compensation No, Accuracy +/-0.2 Percent, Function Measures the Concentration of An Aqueous Solution By Measuring Its Refractive Index, Features Double Hinge Daylight Plate, High Quality Optical Glass Material, Metal Prism Housing, Non Roll Stand, Rubber Grip and Hood On Eyepiece, Scale Display, Zero Ring Calibration, Length 16 1/2 in, Width 4 in, Height 4 in, Includes Disposable Pipette, Nylon Carrying Case This product contains a chemical that is regulated under California Proposition 65. Warning: This product contains a chemical known to the State of California to cause cancer. -