Very warm "like a kotatsu" socks Okamoto Okamoto Socks Supplement Anyway, it's warm. Warmth that gently envelops you The secret to warmth is the ankle Special insulation, heat-generating material used Relaxed fit Softly enveloping your toes, it feels like you're in a kotatsu. Okamoto's uniquely developed special insulation and heat-generating material has made warmer socks possible. The secret is the thermal stimulation of the ankle. The ankle, which tends to draw in coldness, is covered with a heat-generating material. The San'in-ko (acupressure point) area of the ankle is warmed by thermal stimulation. Limited color: Mocha Brown Size: 23-25cm Material: Acrylic, wool, others