DURAN is a brand name for the internationally defined borosilicate glass 3.3 (DIN ISO 3585) produced by the German company DURAN Group GmbH since 2005 under license from the Schott AG, which was the first to develop it and sold it from 1893 until the equity carve-out of the DURAN Group in 2005. Because of its very high resistance to heat and temperature changes, as well as its high mechanical strength and low coefficient of expansion, DURAN, which is similar to Pyrex from Corning, is not only used for laboratory devices (e.g. components of chemical devices, beakers, Erlenmeyer flasks, etc.) but also in cathode ray tubes, transmitting tubes, and speculums.
This glass was developed by Otto Schott in 1887. In 1938 the brand DURAN was subscribed at the Reichspatentamt and registered in 1943