Merrell Hydro Runner Outdoor Shoes Constructed with an EVA shell for a lightweight and flexible fit, the Hydro Runner is the perfect choice for staying cool on busy days. EVA upper for comfort EVA shell for a lightweight and flexible fit Breathable mesh lining 100% recycled integrated EVA foam insole Lightweight - high rebound EVA foam midsole for stability and comfort Merrell sticky rubber outsole - durable traction that grips where you need it presents