The bison down blend bed sock is here! Warmth without weight; comfort without restricting circulation. Your own body heat held where it belongs - gently inside - by some of natures finest insulation. The sock slips gently over the ankle with a rolled top and no restricting elastic. The entire sock is knit in a terry loop with a over plating of nylon on the foot bed and heal. Top of sock reaches the ankle, 3 inches from the heel. A great sock for anyone with a concern with constriction around the ankle.