This baby sleep sack is made with organic cotton fabric and fluffy polyester filling super soft and breathable for comfort and the warm sleep sack is ideal for cooler weather. The three layer breathable material and sleeveless design helps regulate baby temperature reducing overheating risk and ensuring warmth and cozy. These baby sleep sacks are CPSC certified for your baby safety and comfort and 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 allows for natural hip development. The unique quilted design ensures even distribution of fill prevents lumping or shifting improves durability while reduces shrinkage compared to regular baby wearable blanket and withstands hundreds of washes. Our baby wearable blanket features a double zipper so you can unzip from the bottom to change diapers and disturb baby even less during the night and zipper protectors on the top will protect baby jaw from scratches.