Altra Superior 2 Men A1552 Mesh rubber sole Designed To Improve: Running Form, Toe Splay, Stability, Traction, Comfort, Trail Protection Cushioning: Light Outsole: Sticky Rubber TrailClaw Insole: 5 mm Contour Footbed with Removable StoneGuard Rock Protection Other Features: Natural Ride System, Trail Rudder, GaiterTrap Technology