These Sasaki Series sports socks are in high demand and difficult to purchase, constantly selling out. Apparently, wearing these socks supposedly boosts various potentials, making them a very popular product. I purchased a set of two because the single socks were sold out. However, the size felt tight, and it was difficult to wear them (maybe that's how they're supposed to be). Therefore, I am listing the other, brand-new, unopened pair. For more information, please search for "Sasaki Sports Socks." The size is said to be from 26 cm to 28 cm. They are toe-round socks.