Synthetic SUPERIOR TRACTION: Non-slip grip rubber outsoles provide the best traction available for those times when you really need it – like when you’re navigating fast-moving whitewater river beds or rocky beaches. MESH THAT BREATHES LIKE SKIN: Mesh panels that allow air and water to flow through swiftly are critical to your comfort and ability to move quickly. Helps your water socks dry super fast. STRETCH NEOPRENE UPPER: Incredibly easy to pull on and off – even when feet are soaking wet. Gives your feet an extra layer of protection from sharp rocks, shells, glass, and whatever else lurks beneath the waves. SECURE FIT: Big Mens Sizes 13,14 and 15 come with a Strong Adjustable Fabric Closure and Heel Pull Tab. Easily secure your Big Extra Size Aqua Socks with the strong fabric closure – they won’t come off your feet until you take them off. Comes in 3 popular color combinations. NO QUESTIONS ASKED 30-DAY GUARANTEE: No need to guess – take a full 30 days to ensure they fit. If they don’t meet your expectations, simply return them unworn for a no questions asked refund.