The Lightweight Running Shoe That Will Do It All, No Matter The Terrain– The Fast-Trac Nitro 2 Has Dropped. It Delivers A Smooth Ride And Ground-Feel On Surfaces Including Including Loose Trails And Gravel, Thanks To A Full-Length Nitro Infused Top Layer Embedded In The Profoamlite Midsole. Add To That The Durable Pumagrip-Atr Outsole And Integrated Eyestays For A Snug Fit, Along With Details At The Toe That Help Drain And Protect From Debris – And You're Golden With This Ground-Breaking Shoe Made For All Runners In All Four Seasons.