The Series 6M laboratory valves are designed using the plug valve principle. Unlike the ball valve, the shut-off body here comprises a tapered plug. The plug is matched to the valve housing and secured by the hexagon nut. The bore for the plug is exactly aligned with the axis of the housing bore. The flow can be opened and closed by turning 90°. A major advantage in practice is that there is no dead volume in the plug valve. For this reason each tapered plug is allocated to a valve housing and precision matched. The tapered plugs are not interchangeable. The Series 6M laboratory valves are small and compact and available in three different versions. Due to their small nominal diameter they are particularly suitable for use in the laboratory.