HIGHLY COMPRESSIBLE OPEN REINFORCING CORD

A cord () comprises a single layer () made up of N helically wound metal filamentary elements () having an outer diameter D, the metal filamentary elements () defining an internal enclosure () of the cord of diameter Dv. Each metal filamentary element () has a diameter Df and a helix radius of curvature Rf. With this cord (), D, Dv, Df and Rf being expressed in millimeters: 0.10≤Jr≤0.25, 9≤Rf/Df≤30, and 1.60≤Dv/Df≤3.20, where Jr=N/(π*(D−Df))×(Dh×Sin(π/N)−(Df/Cos(αx π/180))) and α is the helix angle, expressed in degrees, of each metal filamentary element ().