The Rudolph Research J257 Wide Range Refractometer was developed by working together with laboratory refractometer users from the polymer, petroleum, petrochemical, pharmaceutical and essential oil industries. The J257 is a fully Automatic, Digital Refractometer, featuring electronic cooling and heating with an extended Refractive Index (RI) measurement range. The J257 is part of the Rudolph Research Rudolph Research Refractometer Product Line.