Luxuriously Gentle Bamboo Rayon Fabric: Experience the soft touch of the HopeTiger baby sleep sack, made with 95% bamboo rayon and 5% spandex. Its silky bamboo Rayon texture is kind to your baby's sensitive skin, and the breathable, lightweight material ensures comfort throughout the day. Plus, its natural moisture-wicking properties contribute to a restful sleep. Optimal Temperature Control with 1.0 TOG: Designed for room temperatures between 68°F and 74°F, the HopeTiger sleep sack features a lightweight, airy design. Its roomy fit supports your baby's leg movement and aids in preventing hip dysplasia, making it an ideal choice for a safe and comfortable sleep. Convenient Double Zipper & Neck Zip Guard: Changing diapers becomes a breeze with HopeTiger's baby sleep sack, equipped with a dual zipper system and a soft zip guard at the neck. This thoughtful design ensures quick diaper changes without disturbing your baby's sleep, offering both convenience and security. Universal Design for Babies 0-18 Months: