The J257 refractometer, which we recently purchased from Rudolph has been a valuable addition to our laboratory. It has provided us with consistent and accurate readings for both research and production. Thus far we have not encountered any problems and I feel confident we have purchased a dependable instrument. Because we are growing as a company, our emphasis on quality has increased. The problems with inconsistency due to employee interpretations with our old instrument are no longer. I would not regret recommending this instrument and Rudolph to anyone.