The adidas UltraBoost 21 ‘Black Silver Metallic’ adds subtle neon accents to an otherwise neutral colorway of the brand’s flagship runner. ‘ULTRABOOST’ is printed in Solar Yellow lettering across the molded heel counter, adding rearfoot stability to a black and grey knit upper that incorporates Primeblue — recycled high-performance materials including Parley Ocean Plastic. Responsive cushioning arrives via a full-length Boost midsole, featuring an exaggerated heel curve that allows for the addition of more Boost capsules.