We pioneered the use of a unique hydrophilic membrane that's 100% waterproof yet pulls moisture away from your skin at the molecular level -- keeping you dry and cool all at the same time. With a Hydrostatic Head of >20,000mm and the addition of Hydrostop technology, which creates a barrier between your skin and the sock to help prevent water from coming in through the top of the sock, our socks stay waterproof under the toughest of conditions.
Please note that due to the close bond between sock cuff and skin, over prolonged use, some people may experience minor skin irritation due to the Hydrostop barrier rubbing against the skin. For those who experience any irritation, we recommend that Hydrostop socks are only used outdoors and not for a prolonged period of time.
Our 100% waterproof socks are constructed using premium materials and by bonding three layers together to make one highly waterproof and breathable sock:

• Outer Layer - 94% Polycolon, 6% Elastane
• Middle Layer - 100% Hydrophilic Membrane
• Inner Layer - 75% Bamboo Rayon, 23% Nylon, 2% Elastane

Sealskinz Waterproof Warm Weather Ankle Length Sock with Hydrostop - Neon Yellow/Black/White