Primaloft is a cut staple fiber used predominantly as insulating fill in sleeping bags and apparel. It was only a matter of time before it would be woven into a blend of fibers and made into socks (and it should come as no surprise that we may see base layers and sweaters woven from Primaloft soon).
With a composition of 75% Primaloft Yarn, 15% nylon, and 10% Lycra, one gets the impression that this sock is pretty lofty, and that Primaloft isn't an afterthought, but rather, the core fiber in this sock. But Primaloft Yarn is actually a blend of Primaloft fibers and merino wool. Still, should we not be skeptical of marketing copy promoting a "new technology" in a category so overcrowded with lookalikes?
From the packaging: "Primaloft Yarn is an optimal blend of Primaloft fibers and Merino Wool. The result is a super soft feel with superior wicking and drying properties compared to socks made only of Merino Wool."
Which leads me further to the conclusion that performance socks are finding it increasingly more difficult to differentiate themselves, which means that for you, it may just boil down to fit and durability. And this sock fits well - especially in my randonee ski boots - these socks are thin and tall and snug. How long they will stay snug, I cannot tell yet, but at 10% Lycra content, they might retain their shape for some time. As for durability, Lorpen Primaloft Light Hiker socks do promise some hope, as well: a bilayer construction keeps the Primaloft/merino yard the on the inside (where the Merino is free to control next-to-skin climate) with the nylon on the outside (for abrasion resistance).
Weight: 2 ounces. MSRP: $19.95. Available: Now