TrekSta Men's T811-Assault GTX Hiking Boot 100% Synthetic Rubber sole NestFIT system cradles your feet, accounting for every contour as it follows the natural flow and design of the foot. Upper, midsole, insole and outsole work together like never before. Ice Lock / HyperGrip sole provides traction in any condition Triple Density Eva insole supports the arch, cushions key strike zones, and strengthens your stride