다운 refers to the soft, fluffy feathers found beneath the tougher exterior feathers of birds, particularly waterfowl like ducks and geese. These feathers provide excellent insulation, keeping the birds warm in cold environments. Due to their lightweight and insulating properties, 다운 is often used in products like jackets, sleeping bags, and comforters. In the textile industry, 다운 is highly valued for its ability to trap air and retain heat. It is commonly categorized by fill power, which measures its loft and insulating efficiency. High-quality 다운 products are sought after for their warmth-to-weight ratio, making them popular among outdoor enthusiasts and those seeking comfort in colder climates.