The adidas UltraBoost 21 in the 'White Solar Yellow' colorway combines a classic white and black design with vibrant flashes of fluorescent color for an eye-catching look. Building upon the success of its predecessor, the UltraBoost 20, this iteration offers an impressive 6% increase in Boost cushioning for enhanced comfort and responsiveness. Additionally, a new Torsion system has been incorporated, resulting in a 15% boost in forefoot stiffness to provide an even more dynamic running experience. The upper boasts a breathable Primeknit material that ensures a snug, sock-like fit, while also prioritizing sustainability through the use of Primeblue construction. By employing recycled Parley Ocean Plastic, adidas continues to make strides in their commitment to reducing environmental impact.