3-valve and 5-valve manifolds are used where relative pressure transmitters are installed. They enable essential operations to be performed on the transmitters, such as starting up a transmitter or setting the zero position in conditions of static or atmospheric pressure. The five-valve manifold also enables a calibrator to be connected for metrological testing of the transmitter. The VM-3 and VM-5 have a modern lightweight construction. The high precision of manufacture enables individual valves to be opened and closed easily.