In March 2017, a collaboration between renowned fashion designer Stella McCartney and Parley for the Oceans resulted in the creation of the Ultra Boost X. This particular shoe, an uncaged low-profile runner, stands out with its remarkable adaptive arch that molds perfectly to the shape of the foot. Its Chalk White finish lends a monochromatic aesthetic to the overall design. The shoe's upper is crafted from Primeknit material, making use of Parley Ocean Plastic, a specialized performance yarn that is formulated from recycled ocean plastics. Completing the shoe is a Boost midsole, adding cushioning and support to every step.