Smartwool Unisex PhD Pro Wader Socks Just because a river gets a lot of pressure, doesn't mean you have to. Our PhD® Pro Wader sock was designed to combat pressure in deeper water to help keep your feet warm and comfortable even when you've been in a river all day. And with our Indestructawool technology, a 4 Degree elite fit, and ventilation channels, you'll wonder how you used to fish before you had this sock. Indestructawool technology features a patent-pending construction method for exceptional durability and comfort. Mesh ventilation zones provide optimum moisture management and maximum breathability. Heavy impact absorption and warmth for extended excursions. Features: Virtually Seamless toe Achilles strap provides extra protection and warmth Ventilation channels in the body of the sock provides breathability Fully cushioned foot and ankle to relieve water pressure on wader bootie Made in USA of Imported Yarns: 76% Merino Wool, 23% Nylon, 1% Elastane