The Stella McCartney x women’s UltraBoost 2020 'Snakeskin Boost' blends sustainability with fashion, highlighted by a black and grey knit upper constructed from Primeblue yarn, which is made with upcycled ocean plastic waste harvested from beaches and coastal communities. The performance runner rides on a snakeskin-printed Boost midsole, supported by a grippy Continental Rubber outsole underfoot.