Boost: Temperature-Independent Cushioning Provides Maximum Comfort And Energy Return In All Climates. | Fit Counter: Supportive Heel Construction Designed To Enable The Free Motion Of The Achillies Tendon | Prementioned Knit Provides Enhanced Breathability And Ventilation Around Key Sweat Zones Under The Cage And In The Forefoot. | Stretch web With Continental: Rubber Outsole With Superior Grip That Adapts To Every Runners Foot Strike By Moving In Harmony With Boost To Provide A Smoother And More Flexible Ride.