The Siren Ventilator from Merrell has a highly ventilated design that lets the air flow through while mesh lining wicks away moisture. Uppers combine synthetic and full grain leather with breathable mesh. Vibram Siren sole adds stability and traction you need for speed hiking or trail biking. Q-Form triple-density molded footframe promotes healthy alignment for a womans stride. The Siren Ventilator features Slip Lasted Construction. Full Grain Synthetic Leather and Breathable Mesh Upper. Breathable Mesh Lining. TPU Injection Molded Heel. 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 and Vibram Siren Sole TC5Plus Rubber.