Last year's highly popular "Just Like a Kotatsu" series, which warms you from the feet up, now has a similar sock type. Size: 23-25cm (for women) Material composition: Acrylic, wool, and other With a unique knitting method, it warms the San Yin Jiao point, an acupressure point on the ankle that protects against cold, and keeps your toes warm. The "necks" – ankles, wrists, and neck – are points where blood flows intensively.