In 2015, adidas introduced the revolutionary UltraBoost technology which combined the Primeknit, Boost, and Torsion engineering features. This groundbreaking technology can also be observed in the UltraBoost 3.0 'Grey Four' sneaker, where the original shoe's technical elements are still present. The Primeknit upper of this shoe showcases an integrated Three-Stripes cage on the quarter panels, which is intricately woven with wool yarn. Additionally, the UltraBoost is enhanced by a flexible four-way stretch mesh heel and an S-Curve heel counter, both providing extra support. Furthermore, the underfoot Torsion system reinforces the overall structure of the shoe.