Now in their fourth iteration, the Ultra Fastpack Shoes just keep getting better. This mark IV version features a breathable-waterpoof Fututelight™ membrane. Springy, OrthoLite® X35™ Hybrid™ footbeds are cushioning, but also responsive and along with the FastFoam™ midsoles maximise energy return for a more efficient trek. The Ultra Fastpacks are engineered specifically for moving quickly over tough trails: the lug design is optimised for undulating, rocky terrain; the Vibram® Megagrip™ does exac