Ribbed socks made with American Sea Island cotton with an average fiber length of 49mm. The natural oil content in this cotton is higher than regular cotton giving it a silky and supple texture. Knitwin Co., Ltd. began in 1950 just after World War II. Katsuji Nishiguchi founded the company with a single hand-operating knitting machine. It is currently operating under third generation director Isato Nishiguchi. Today, Knitwin co,.Ltd has evolved and expanded into a sock manufacturing company housing over 130 knitting machines. Our team of professionals consists of veterans with over 50 years of experience, all of whom take equal part in creating and sharing socks that will change your tomorrow. - 80% cotton, 19% polyester, 1% polyurethane. - Machine wash cold, line dry. - Made in Japan.