adidas Women's Ultraboost w Running Shoe, Black/Black/Black, 9 M US 100% Synthetic Imported Rubber sole Weight: 9 ounces (size 7); runner type: natural; midsole drop: 10 mm (heel: 30.5 mm / forefoot: 20.5 mm) Boost's energy-returning properties keep every step charged with an endless supply of light, fast energy Stretch web rubber outsole is lightweight and elastic, adapting to the ground for stability and working strategically to optimize the unique properties of boost from touchdown to push-off Adidas prime knit is carefully engineered to naturally expand with your foot while you run to give you a more comfortable fit and help reduce irritation; sockfit upper for a snug, supportive fit Torsion system for midfoot integrity; fit frame 3d-molded tpu helps increase stability around the heel; continental rubber outsole for extraordinary grip in wet and dry conditions