50% merino wool, 37% acrylic, 10% polyamide, 3% elastane. Merino wool for temperature regulation and moisture absorption. Acrylic for extra softness so you don't feel any itch from the wool. Polyamide used for reinforced heels and toes for increased strength and durability. Sizing: Medium is suitable for: Womens US shoe size 6-9 / Mens size 5-9. Large is suitable for: Womens US shoe size 9-14 / Mens size 10-12. Made in Ukraine.