An automatic flow rate control valve, includes a tubular body, defining a flow path between inlet apertures having a gradually variable cross-sectional area and a fluid outlet at one end; a flow control piston is axially movable within the tubular body, under opposite actions of the fluid pressure and a biasing spring, to choke the fluid inlet apertures, while maintaining a constant flow rate. Recovery is enhanced by the use of backward and forward pointers between data and mapping elements for the data elements in the order written by the management algorithm. The ink supply side of the carrier defines a number of discrete feed formations being configured to receive ink of a particular colour. The composition yet further comprises and a solubilizer. The power amplifier circuit board and the transceiver circuit board are respectively located at two end portions of the duplexer. By virtue of the foregoing, the memory package density of the assembly can be increased without increasing the height or area consumed by the assembly for receipt within an existing external housing.