SIZE CHART - M : Men Shoe 7-9 / L : Men Shoe 9-11 / XL : Men Shoe 11-13 NEVER SLIP OFF - With 47 year experience, Pro Mountain Socks is true Anti slip off, Made in Korea. FUNCTION FOR FEET - Cushioned padded ball reduces blister, absorb sweat. Instep mesh wicks moisture. LOW ENOUGH FOR MOST - invisible for most casual athletic sneaker shoes. Not for super low loafers. NATURAL YARN FOR YOUR SKIN - Warm cotton comfy sox without irritation. Good for wide feet. 47 years of craftsmanship - Pro Mountain Socks. The seamless no show socks came out with founder's last investment on socks. Truly seamless, comfortable just like your second skin with thick cushioning for cold weather and sweat absorbing.