The adidas UltraBoost 21 'Halo Silver' boasts an understated greyscale design, putting the shoe's impressive performance features in the forefront. This updated version features a revamped Boost midsole with 6% more Boost capsules compared to its predecessor, ensuring enhanced cushioning and energy return. Additionally, the Torsion system has been reworked to enhance forefoot rigidity, resulting in a more responsive and dynamic running experience. The upper of the shoe is crafted from a knit material that aligns with adidas' commitment to sustainability, utilizing Parley Ocean Plastic and other recycled high-performance materials.