1.Cotton2.MATERIAL: The baby winter sleeping sack is made of natural organic cotton lining and fabric, soft, comfy and breathable3. LARGE HEM: Wearable blanket with separate legs, great for unisex toddlers who walk or sleeping, will not be kicked off. We widened the hem part to create more room for baby to stretch, making your baby more comfortable and free from restraint4.DETACHABLE SLEEVES: Detachable long sleeves could be adjusted to fit different temperatures, care for baby's sleep5.CONVENIENT 3 ZIPPERS: Three way zippers unzip from top and bottom for easy dressing and quick diaper changes. High quality zippers are well made, will not broke