Sensor manifolds include a housing having at least two fluid flow passages communicating with fluid entry and exit ports in the housing that are connectable in line in a full flow fluid line in a system. A unitary fibrous structure comprises a plurality of cellulosic fibers randomly distributed throughout the fibrous structure, and a plurality of synthetic fibers distributed throughout the fibrous structure in a non-random repeating pattern. The present invention has the following advantages in comparison with the prior art. Components 103 to 109 are connected to a power management circuit 110, including an Integrated Circuit 111, mounted on the PCB 102. The proposed technical solution is suitable for use with stones of any cut.