The adidas UltraBoost 21 'Crystal White Hazy Green' draws attention to the running shoe's complete Boost midsole, which is adorned with a shiny iridescent coating. This innovative midsole provides excellent responsiveness and comfort, and it is further enhanced by adidas' Linear Energy Push torsion system and a durable Stretchweb Continental rubber outsole. The upper part of the shoe showcases a breathable Primeknit construction in Crystal White that incorporates recycled Parley Ocean Plastic and excludes any virgin polyester. To ensure stability and support, the shoe boasts a molded heel counter in the refreshing shade of Hazy Green.