This is a new generation refractometer that has been specially made for GemologyEquipment.com. This new unit offers a CZ hemicylinider rather than the traditional soft glass. The long term durability for this unit is excellent. It also comes with a specially designed RI Liquid dispenser that is far safer than anything on the market. And the unit is self contained with a special monochomatic LED light that operated on battery or on 110v electrical. Finally, it comes with a specially made aluminum case that is especially designed to protect this wonderful refractometer from wear and tear. This is the finest refractometer we have tested in years. And we have personally tested all of our new equipment to guarantee the quality and value of every equipment item you purchase from the International School of Gemology. Please Note: We do not provide training nor manuals with individual gem equipment purchases.