These heavy-duty socks are crafted with premium-quality linen threads, ensuring unmatched strength, superior sweat absorption, and quick drying. UES produces these premium socks using low-gauge knitting machines. Combined with a substantial cotton content, this method creates a distinctive flecked texture. Made in Japan. Linen 65%, cotton 31, Nylon 2%, polyurethane 2% Tag indicates size XL but these fit more like a US Small-Med. Japan sizing is sometimes tough to gauge.