A sleep sack is a wearable blanket designed to keep babies warm and safe while they sleep. It typically has armholes or is sleeveless, allowing for freedom of movement while preventing the baby from kicking off blankets. Sleep sacks come in various materials and sizes, catering to different ages and seasons. These products are often used as an alternative to traditional blankets, which can pose a suffocation risk for infants. Many sleep sacks are made from breathable fabrics and are available in different TOG ratings, indicating their warmth level. Parents often choose sleep sacks for their convenience and safety features.