100% Cotton Imported Winter Warmth - Featuring a plush heart-shaped polka dot surface made of polyester wool with a 100% cotton lining, the fleece sleep sack has a double-layer design for superior warmth and comfort, creating a cozy embrace for your baby and helping to soothe him or her to sleep Healthy Growth - Our baby sleep sack are thoughtfully designed to support the healthy development of your baby's hips by providing enough room for their legs to move freely 2-Way Zipper - Toddler sleep sack is equipped with a two-way zipper, while the zipper protection design ensures that your baby's delicate skin is protected from scratches, and the durable, smooth zipper makes nighttime diaper changes easy and simple Safe Sleep Design- Designed for baby's comfort and parent's peace of mind, every detail of the JELLYMONI Infant Sleeping Bag meets high safety standards and complies with the guidelines of the U.S. Consumer Product Safety Commission (CPSC), giving parents the peace of mind that their little one is sleeping safely and comfortably 4 Sizes - 1.5 TOG Fleece sleep sack for 0-24 months baby, S for 0-6 Months, M for 6-12 Months, L for 12-18 Months, XL for 18-24 Months, choose the perfect size according to our detailed size chart for the best fit 100% Cotton