Reaction vial, cylindrical, graduated with groove in the flat flange. The reaction vial is enclosed in a tempering jacket. The tempering jacket has two connection pieces (either GL threaded connection (GL 14 or GL 18) or ball flange connection (ball flange-ball; KF 15 or KF 25). The flat flange reaction vial is closed with a lid which is available separately. Both parts are held together by a clamping ring. A sealing ring, or the use of grinding grease, prevents the grinding surfaces from jamming. Suitable silicone and FEP sealing rings are available separately. The flat flange vial can be combined with other components (e.g. coolers, stirrer shafts and dropping funnels) by means of various standard ground joints in the lid.Applications: preparatory work, such as general reactions, distillation, evaporation and drying, which produce solid or viscous substances.