K-Swiss K Ona Ironman Womens Running Shoes Synthetic Rubber sole An ultra-light, well cushioned and stable running shoe perfect for fast days, races and triathlons Flow Cool moisture management system located from heel to toe to keep feet cool and dry Rigid TPU midfoot shank for stability, durable K-EVA midsole enhances cushioning Superfoam? technology and an Si-18 Technology crash pad offers cushioning and comfort The Aosta? II rubber outsole provides durability