These women's Ultraboost shoes are designed to give runners the comfort and responsiveness they need. An adidas Primeknit upper is stretchy and has a sock-like fit. A Linear Energy Push system increases forefoot and midfoot stiffness. The S-curve heel eliminates slip, and the signature Boost cushioning returns energy to your stride.-core black/core black/blue oxide-product ID: FY0405RED MARK ON SZ TAG TO PREVENT FRAUD RETURNS! PURCHASED DIRECTLY FROM ADIDAS OUTLET.