Montrail Men's Caldorado Trail Running Shoes synthetic-and-mesh Full length FluidFoam Midsole - Soft, responsive cushioning from heel to toe. FluidGuide Midsole Technology - Adapts to ever-changing terrain and provides the smoothest possible foot guidance and multidirectional stability. Forefoot TrailShield - A lightweight, flexible material that is co-molded between outsole and midsole for underfoot protection from rocks, roots, and other trail debris. Seamless Upper - Delivers a fit free of irritation. Thermoplastic Midfoot Frame - Inherent stability through the midfoot.