Lightweight, breathable, and comfortable the Under Armour SpeedForm Fortis 2.1 is ready to pick up the pace, mile after mile. Seamless UA SpeedForm upper construction wraps and supports the foot for a snug fit that moves with you. Internal heel counter holds the foot firmly in place over the footbed. Two-piece Charged Cushioning layers soft foam over a denser base for the perfect combination of comfort and responsiveness. Solid rubber in high-wear areas of the outsole for durable traction where you need it most. Anatomically placed flex grooves encourage a smooth transition from heelstrike to toe-off.