The adidas UltraBoost 21 Cold.Rdy ‘White Signal Green’ showcases fluorescent accents on a performance running shoe made for the cold-weather months. Made in part with 50% recycled materials, the white Primeknit+ upper features no-sew overlays and a molded heel counter with UltraBoost branding in embossed green lettering. The sock-like build is lined in insulated black textile and accented with a neon green pull tab at the heel. A metallic teal hue is applied to the stacked Boost midsole, supported by a Continental WinterGrip Rubber outsole.