Down insulation is made from the soft, fluffy undercoating of birds, primarily ducks and geese. This natural material is known for its excellent thermal properties, providing warmth without adding much weight. Down clusters trap air, creating an insulating layer that helps retain body heat, making it a popular choice for jackets, sleeping bags, and comforters. One of the key benefits of down insulation is its compressibility, allowing it to pack down small for easy storage and transport. However, it is important to note that down can lose its insulating properties when wet, so many products use a water-resistant treatment or combine down with synthetic materials for added durability and performance in various conditions.