A Siren that responds to the urge to surge. But with a full grain leather upper and rubber bumpers at toe and heel it is built for durability. Merrell Air Cushion midsole with women-specific Q-Form technology smoothes out strides while maintaining alignment. Vibram Siren sole features heavier lug pattern in high-friction areas and tread for vital traction under the arch. End Uses: Light hiking or biking on trails or urban terrain in dry conditions. Best worn with mid to light weight socks. Slip Lasted Construction Full Grain/Synthetic Leather and Breathable Mesh Upper Breathable Mesh Lining 4.5mm Anatomical Footbed Nylon 6.6 Injection Molded Arch Shank Q-Form Triple Density Compression Molded EVA Footframe Air Cushion Midsole 5mm Sole Lug Depth Vibram Siren Sole/TC5+ Rubber Weight: 1 lb.