The original, military-trusted sock, enforced with Hydrostop. A men’s and women’s waterproof sock, the Briston thrives in multiple environments. Hydrostop prevents water dripping down leg into sock. Lightweight and breathable. Handcrafted in 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. Durable nylon exterior, with 4-way stretch for an optimal fit. Aquasealz waterproof membrane releases body-generated heat and moisture, while denying intrusion of external elements. Premium merino wool and acrylic blend for softness, sweat-wicking and odour resistance.