The adidas Ultra Boost 21 Core Black is a running shoe from the Ultra Boost 2021 collection in a Core Black colorway. This shoe features an upper made of PRIMEBLUE, a recycled high-performance fabric made from recycled polyester from Parley Ocean Plastic. The upper also features a semi-translucent lace cage, a tonal adidas mountain logo branding on the tongue patch, and an Ultra Boost-branded back heel counter. This shoe rests on a chunkier sole unit with an improved Torsion system, comprising a White midsole and a rubber outsole with additional 6% Boost capsules for a firm stride. The adidas Ultra Boost 21 Core Black was released on January 28th, 2021, it retailed at $180.