In the interest of durability and support, with this Siren we stopped just short of nothing but net. But a breathable mesh upper and mesh lining go with the flow. Thin, sculpted leather strapping provide lightweight but effective soft buttressing. Merrell's proprietary combination of women-specific Q-Form alignment in an Air Cushion midsole smooths out footstrike and improves stride efficiency. 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. Vibram Siren sole/sticky rubber. Available Colors: Desert Sage, Grey/Lime, Blue Slate.