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 which sold it from 1893 until the equity carve-out of the DURAN Group in 2005. Because of its high resistance to heat and temperature changes, as well as its high mechanical strength and low coefficient of thermal expansion, DURAN, which Pyrex from Corning is similar to, 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.