Glass laboratory filtering flask (Buchner flask) with side arm, 250ml capacity, manufactured by Pyrex

Laboratory filtering flasks, also known as Buchner flasks, have been essential scientific equipment since the late 19th century when German chemist Ernst Büchner developed the vacuum filtration technique. Pyrex, introduced by Corning Glass Works in 1915, revolutionized laboratory glassware with its borosilicate glass formula that could withstand thermal shock and chemical corrosion. These specialized flasks feature a side arm for vacuum connection and graduated markings for precise measurement, making them indispensable in chemistry and biology laboratories for separating solids from liquids through vacuum filtration. These flasks appeal to science educators, laboratory equipment collectors, vintage scientific instrument enthusiasts, and home chemistry hobbyists. Pyrex laboratory glassware is particularly valued for its durability, precision manufacturing, and iconic brand recognition. Collectors and working laboratories alike appreciate authentic Pyrex pieces for their superior quality, clear manufacturer markings, and reliable performance. The combination of practical utility and historical significance makes vintage Pyrex laboratory equipment sought after by those who appreciate the evolution of scientific instrumentation and the standardization of laboratory practices throughout the 20th century.