A method comprising encapsulating a message with a tunnel header comprising an access identifier associated with a network entity. The method includes: compacting a raw powder containing a matrix forming powder and a hard phase forming powder into a green compact, the matrix forming powder containing 90 mass % or more of a powder having the maximum particle diameter of 46 \u03bcm, and the hard phase forming powder being 40 to 70 mass % with respect to the raw powder; and sintering the green compact. It is proposed that a first region has stop faces where these stop faces, in the case of an energy guide chain composed from link plates, determine a curvature region in a transition region between a lower trunk and upper trunk of the energy guide chain. The remainder has 2 to 6 wt % CaF2 as an essential component, and an average particle size of said CaF2 is controlled to fall within the range from 40 \u03bcm to 350 \u03bcm. The inductor is formed from a ribbon of conductor wound around a magnetic core, and further includes electrostatic screens positioned between successive windings of the conductor to provide capacitive screening, substantially reducing high frequency voltage signals propagating from one end of the inductor to the other.