A special welding on the tip of the spike with the "cemented hard" alloy used for space development equipment and tunnel excavators. Upper: Synthetic leather, artificial leather, synthetic fiber; Sole: Synthetic sole; Color: Black x Black; Spike: Metal (fixed with carbide tip hardware); Size: 10.0 - 11.8 inches (25.5 - 29.0 cm), 11 GM18000