Krüss offers over twenty models in the HR series of Manual Handheld Refractometers, designed for the determination of mixing ratios, quality and quantity inspection applications within a large range of industries. The HR range has been designed for quick daily usage. It is compact, sturdy and simple to use, measurements are easily read, and is suitable for most applications because of the various scales and functions. For calibration either distilled water or a small calibration plate is employed, depending upon model. The HR is supplied in a case, complete with conversion tables.