Seamless Primeknit upper for a snug, sock-like fit that stretches and moves with your foot for a truly one-to-one fit. Knit collar creates a soft, sock-like opening, helping the shoe fit as an extension of your foot. Full-length boost midsole cushioning is ultra light and ultra responsive, absorbing the force of impact and returning that energy at toe-off, propelling you to a faster, more comfortable run. TORSION SYSTEM adds lightweight stability, encouraging a smooth, more natural transition from heelstrike to toe-off. 10mm offset. StretchWeb outsole construction adapts to your unique footstrike, allowing the boost midsole particles to freely expand and contract with the natural movement of your foot. Wt. 9.8 oz.