You'll rarely find a lightweight hiking sock with the same reinforced heel/toe protection and strength weaved into these heavy duty boot socks… but look no more. The breathable Merino wool blend of the Kenetrek Yellowstone sock insulates when wet, resists odors, and helps regulate your temperature from summer into early fall. Wicking, long-lasting and built for the trail. Mens shoe sizes: Medium(5-8), Large(9-12), X-Large(13-15) Womens shoe sizes: Small(4-7), Medium(8-9), Large(10-11)Made in the USA. Kenetrek Yellowstone Socks KE-1241