Gray socks with heat retention properties, made using Kishu Binchotan charcoal. - Color: Gray - Size: 22-24cm - Material: Rayon, Kishu Binchotan charcoal - Features: Negative ion effect, heat retention These were given to me previously. I opened the product once for inspection, but the elastic at the opening and the rest of the sock are in good condition, and they seem perfectly comfortable to wear. Please understand that these have been stored at home. Thank you for looking.