As a running shoe that seeks to keep your feet comfortable and active, what could be improved? Perhaps the answer is to further enhance comfort and vitality. These adidas Ultraboost 21 running shoes have a comfortable foot feel and help you run easily. Includes Boost midsole with Linear Energy Push system to help you walk with ease. Made with Primeblue sports performance recycled materials, including Parley Ocean Plastic. The upper is 50% fabric, of which 75% is Primeblue yarn and does not contain virgin polyester.