A method, system, apparatus, and signal-bearing media for determining connectivity information for routers running on servers that are attached to a device. RF input terminals 101, 102 are applied with signals at phases opposite to each other. The sleeve includes an interior second sinusoidally shaped contour reciprocal to the first undulating contour of the tailpiece. The first mounting member may be located adjacent to a ground engaging member in the forefoot region of the outsole and the second mounting member is located adjacent to a ground engaging member in the heel region of the outsole. The cross section may be of a geometry corresponding to the outer contour of the ring body or shoulders and may have ends bent towards the member-contacting surface.