The Ibiza Platform runs a bit small, please size up by 1/2 a size for the perfect fit. They're made from irresistibly soft leather, so there's no break in period. Base Height: 35mm / 1.4in Materials Upper: Leather Working Group (LWG) Gold-Rated & chrome-free, tumbled managua leather. Insoles: High performance Ortholite insoles featuring open-cell technology. Midsole & Outsole: 20% recycled rubber and 80% virgin natural rubber. Laces: REPREVE 100% recycled polyester.