These flasks offer some advantages over regular round-bottom flasks. Especially with heterogeneous reactions, the better mixing through greater turbulence upon stirring is of advantage. Due to improved stirring, their use in Ullmann reactions and Suzuki-type couplings on a larger scale has led to considerable reduction in reaction time. The ring of deposit around the magnetic stirring bar oftentimes observed with heterogeneous reactions in round-bottom flasks may be avoided if comparing the same-scale reaction in the two flask types. The use of cylindrical flasks may substitute, therefore, for a mechanical stirrer. The two flasks shown have a volume of 1 l each, Joint 24/40. Usable with air-condensers, and all regular attachments.Available in sizes of 50, 100, 250, 500 and 1000 ml and joints sizes 14/19 (50 ml), 19/22 (100 and 250 ml), 24/40 (250, 500 and 1000 ml).