Description of Merrell Siren Sport - Women's 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. Features: 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.