Pure Boost X Training ShoesA light, sleek trainer that returns energy to your workout to keep it charged.The boostâ„¢ midsole on these women's training shoes is a game-changer with its endless supply of light, fast energy. These shoes gently hug feet with sock-like arch support, a lightweight frame and a textile and synthetic upper. A gap in the overlay at the arch supports the natural movement of your foot.boost™'s energy-returning properties keep every step charged with an endless supply of light, fast energyTextile and synthetic upper for lightweight flexibilityAdjustable forefoot and midfoot supportSock-like construction for snug fitAdaptive dynamic fit for optimal flexibility and smooth transitionNON MARKING rubber outsoleImported