Design:Upgraded breathable engineered mesh upperImproved engineered mesh on the upper decreases weight and increases breathabilityPlush collar tongue and sockliner for a secure and comfortable fitMR-10 Last for a consistent fit (same as Pegasus 40)In-Shoe Comfort:ReactX foam midsole surrounds forefoot and heel Air Zoom units for an energized ride All-new ReactX foam midsole is 13% more responsive than previous React technologyDurability & Traction:Signature waffle-inspired rubber outsole for traction and flexibilityAdditional Details:ReactX foam is engineered to reduce its carbon footprint by at least 43% in a pair of midsoles due to reduced manufacturing process energy compared to prior React foamWeight: Approx. 251 g/8.8 oz (Women's US 8)Heel-to-toe drop: 10 mm