Our Warm Hocosa of Switzerland Long underwear pants for Children in smooth fine knitted organic merino wool knit that doesn’t itch. Soft and breathable merino wool can be worn in every season. It breathes with the body, does not cause perspiration and provides warmth even when damp. Woolen underwear keeps the child warm during winter and is also good for a cool summer. Pure natural wool fibers are flexible and breathe even in warm weather. Care Instructions.