With a lightweight Primeknit upper and BOOST foam cushioning, you're in for an out-of-this-world running experience. Seamless Primeknit upper for a close fit and sock-like comfort. ClimaChill provides 360-degree ventilation to keep you feeling dry and fresh. BOOST foam midsole features thousands of energy capsules that store and release energy with every step. Grippy rubber outsole for long-lasting traction. Wt. 8.2 oz.