This vapour barrier sock works by blocking evaporative heat-loss keeping heat and moisture from moving into the insulation of the 200 weight Polartec fleece* as well as the inner boot. The technology has seen a decade of use in the coldest and highest places on earth.
The fabric is VaprThrm® insulation which has a lightweight soft polyester wicking lining, vapour barrier film and Polartec 200 fleece* combined. Product and materials are made in the USA.
The Hi-Rise version is a calf-length cut with the volume in the foot and ankle reduced to eliminate folds and pressure points and give the ideal sock for telemark boots, snowboarding boots and trimmer mountaineering boots.
To quote Andy Kirkpatrick, "These socks are made from a patented fabric called VaprThrm® and are basically thick and thin fleece with a vapour barrier membrane sandwiched in-between. They are designed to be worn alone, with no liner or outer socks and removed at the end of the day to dry. Like any vapour barrier system the idea is that when you reach 100% humidity within the sock your feet will stop sweating and in a traditional sock combo this barrier also stops both your outer sock and boot from getting wet. Unlike a traditional VB combo this system is far slimmer, plus there is no slickness between the layers (all three layers are laminated together). A lightly brushed inner fabric stops your feet getting that ‘foot in a plastic bag’ feeling, with the thin fleecy outer providing warmth and some cushioning. The socks are sewn together with the seams turned outwards and, although you’d expect blisters, as long as they are fitted correctly they are blister-free."
NB Please note that these socks are designed to be used in really cold places with double boots. Worn like this, the little sweat that is produced is kept warm and the feet likewise. Your feet stay warmer because the boot inners remain completely dry and stay so for days on end. With a single boot in milder conditions, your feet will sweat more and that sweat will chill as the boots will not insulate it enough. So, not suitable for Scotland in winter, but great for Alaska, Polar Regions, Himalayas, Alpine winter climbing etc.
They won't fit you if your calves are larger than 37cm in circumference but RBH may make you a custom pair if you contact them directly.
Weight 160g per pair for size 8. Machine washable.
*NB This fleece is nothing like as thick as a Polartec 200 fleece jacket. In practice we have found that using a pair of these socks in place of a pair of Thorlo Mountain socks works fine.