Many applications in chemistry such as separation, drying, distillation, filtration, etc. are conducted under vacuum. So chemical laboratories, both in universities and in industry alike, need a vacuum supply. This must meet the application based, technical requirements regarding pumping speed and ultimate vacuum and frequently also the controllability of these parameters. In addition consideration must also be given to space restrictions, ecological and economic criteria. These constraints mean that it is not always possible to have the technically best solution i.e. each application with a separate pump. Local area vacuum networks offer the most balanced solution in these circumstances. However achieving a fully functional, economic and customer-oriented solution, requires a useful selection, of the appropriate components. VACUU•LAN®, the third generation of VACUUBRAND local area vacuum network, fulfils these requirements outstandingly. An important element is the chemistry non return valve, which is integrated into the basic elements and acts against the cross interference of individual applications and which operates even with small pressure differentials. To the basic element can be added a wide range of flexible, modular components such as manual control valves, an electromagnetic chemistry valve for vacuum regulation with a vacuum CONTROLLER, gauges, T-connectors and so on.