XPOP: A completely new type of midsole compound that delivers cushioning, rebound, and durability at a high level. The exquisite harmony of the super soft and advanced cushioning with high energy return makes you feel as if you are floating on water. This material offers you a running experience with superior comfort that you've never experienced before. U4icX Midsole: A lighter, more cushioned iteration of U4ic, delivering a softer underfoot feeling for a smooth transition. Found in the Wave Enigma, Wave Inspire, Wave Rider, and Wave Prophecy. U4icX Strobel Lasting Board: Ensures a comfortable underfoot feel.