Portlandia World Sling Shoes Hook-and-loop closure helps hold your foot in place and offers a just-right fit. Soft, leather upper features cut-out details for enhanced breathability. Natural cork footbed, made of eco-friendly, biodegradable materials, conforms to the shape or your foot. Durable rubber outsole delivers sure-footed traction. Material Content: leather upper and upper lining, synthetic sockliner, cork footbed and midsole, polyurethane shank, rubber outsole.