Warm 2.5 Tog: Made of 100% cotton fabric and fluffy polyester filling, our winter sleep sack is super soft and skin-friendly to baby's delicate skin. 2.5 TOG sleep sacks are suitable for cold winter and room temperatures from 61℉ - 68℉, keeping your little one warm and comfortable. Safety and Cozy: Unnivoll baby sleep sack has been certified to meet Consumer Product Safety Commission(CPSC), dedicating to ensure your baby's safety. Large bottom space allows infants to move freely but not kick off. Well-fitted neckline and sleeveless design provides more flexibility and snugness. Quilted Design for Durability: Unique quilted stitching ensures even distribution of fillers, sleep sack will not lump or shift. With preshrinking process, our sleeping bag has a shrinkage rate of less than 2% after being washed by machine and low-temperature drying(below 30℃/86℉), making this newborn sleep sack more durable and practical for daily use. Smooth 2-way Zipper: Double zipper allows for easy dressing and convenient diaper changing without disturbing baby while sleeping. Top-quality zippers are smooth and will not get stuck even after being used many times. Zipper guard of sleep sack can protect the baby's jaw from scratches. Essential Baby Item: Our sleep sacks with four sizes for choose; S(0-6 months/10-18 pounds), M(6-12 months/16-24 pounds), L(12-18 months/22-28 pounds), XL(18-24 months/26-34 pounds). As a must-have for parents, baby wearable blanket is suitable for both boys and girls! Unnivoll Baby Sleep Sack