The adidas UltraBoost 21 ‘White Solar Yellow’ presents an elemental white and black colorway of the performance runner enlivened with fluorescent streaks of color. In comparison to the UltraBoost 20, this pair adds 6% more Boost cushioning and a new Torsion system that yields a 15% increase in forefoot stiffness for a more responsive run. Up top, a breathable Primeknit upper delivers sock-like comfort. Primeblue construction, featuring recycled Parley Ocean Plastic, maintains adidas’ sustainability efforts.