Soft and Cozy - This baby sleep sack made with 100% cotton, super-soft and breathable for comfort. Sleeveless design helps regulate baby's temperature, reducing overheating risk and ensuring warmth and cozy. | Safety Sleep - Yoofoss baby sleep sack are CPSC-certified for your baby's safety and comfort. The neckline has been carefully sized and numerous experiments ensure a secure and snug fit, preventing the baby from slipping into the sleeping sack. And the loose around the legs to allow for natural hip development. | Warmth 1.0 Tog: With two layers cotton fabric, the 1.0 TOG baby sleep sack is perfect for all-year-around, keeps baby cozy and comfortable in A/C room or restaurant, when travelling or napping.We insist on quality control of baby wearable blanket, it can be withstand millions of washes and achieve a shrinkage rate of less than 2% after machine washing and dry on low heat (<30°C/86°F). | Smooth 2-way Zipper - Our Baby wearable blanket feature a double zipper, so you can unzip from the bottom to to change diapers, disturb baby even less during the night. Then you and enjoy a sweet night with little one ! Zipper protectors on the top will protect baby's jaw from scratches. | 2 Pack: The package comes with 2 pack sleepsack, so that baby always has one to wear to bed.There are 4 sizes available for your choices: S(0-6 Months/10-18lb), M (6-12 Months/16-24lb), L(12-18 Months/22-18lb), XL(18-24 Months/26-34lbs).Please refer to our size chart carefully before you order our baby wearable blanket.