Down is the soft, delicate and insulating layer of feathers that covers the bodies of birds, especially waterfowl such as ducks and geese. We often use down feathers as an insulating material in clothing, such as down jackets, and sleeping products, such as down pillows and duvets.
Known for its effective insulating properties, down keeps us warm in cold weather conditions.
Source
Textile Exchange – Down – Down is an insulating material with a high warmth-to-weight ratio
November 2023, TÄNKOM | Revised May 2024 RETHINK