Start the day with purpose. When you lace into these adidas by Stella McCartney Ultraboost 21 shoes, you're not just making a commitment to yourself, you're honoring your commitment to our planet. The cage adds extra support to the adaptable and flexible inner sock construction. Every step is fueled by the comfort of Boost cushioning, cheering you on as you push just a bit further. This product is made with Primegreen, a series of high-performance recycled materials. 50% of upper is recycled content. No virgin polyester.