Wigwam Merino Wool Silk Hiker The Wigwam F2337 Merino Wool Silk Sock, is a fine grade of wool derived from merino sheep. Merino wool differs from classic wool by providing a luxurious softness and comfort due to the fine diameter of Merino fibers used. Merino wool does not itch and is shrink-treated so that it will hold its same shape and size after machine washing. The F2337 is made of 65% Merino Wool, 20% Stretch Nylon, 10% Silk, and 5% Spandex.