The original military-grade sock, reinforced with Hydrostop technology. Designed for both men and women, the Briston waterproof sock excels in diverse conditions. Hydrostop prevents water from seeping down the leg into the sock. It is lightweight, breathable, and handcrafted at the Sealskinz factory in Norfolk. Sealskinz three-layer AQUASEALZ composition sees a 100% waterproof hydrophilic membrane enmeshed between a premium merino wool interior and an extra-durable nylon exterior. Outer – Durable nylon exterior, with 4-way stretch for an optimal fit. Mid-Section – Aquasealz waterproof membrane releases body-generated heat and moisture, while denying intrusion of external elements. Interior – Premium merino wool and acrylic blend for softness, sweat-wicking and odour resistance. Hydrostop - Hydrostop is an elastic taping around the inside cuff of the sock. This extra barrier reduces the risk of water dripping down the leg into the sock. Outer Layer - 90% Nylon, 10% Elastane Middle Layer - Aquasealz waterproof membrane Inner Layer - 36% Merino Wool, 36% Acrylic, 18% Polyester, 5% Elastane, 4% Nylon, 1% TPU