The Endorphin Speed 5 is built to go fast and feel smoothwhether you're pushing the pace on track night with friends or you're chasing a PR . A newly designed nylon plate and responsive PWRRUN PB cushioning come together for snappy transitions and a fast ride. This is speed you can count on. Design: New lightweight engineered mesh for an even more comfortable fit, perfect for fast-paced runs and daily wear In-Shoe Comfort: A full-length semi-rigid nylon plate between two layers of responsive PWRRUN foam, giving you a perfect balance of propulsion and cushioning for every stride Durability & Traction: Reconfigured outsole with expanded coverage in the heel for greater durability during your quickest strides Full length groove to enhance the natural cycle of your gait