The F3 sock that is specifically designed to conform to the shape of the foot and around the Achilles heel, and is made with our unique tri-laminate material, so its super comfy and functional. Designed for use in water sports under a neoprene boot or on its own, the F3 sock has a neoprene seal that significantly reduces the water trapped inside the sock. They are warm, stylish and with a functional tread underneath to give you additional grip on slick surfaces. You'll know why our Enth Degree F3 Socks are one of our most popular items when you put them on. We knew we got the design right, when the staff started asking if they could wear them around the office.