100% Polyester Imported Warm 2.0 Tog: Made of comfortable and high quality 100% microfiber polyester, our winter sleep sack is super soft and skin-friendly to baby's delicate skin. 2.0 TOG sleep sacks are suitable for room temperatures from 64℉ - 70℉, 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. Well-fitted neckline and sleeveless design provides more flexibility and snugness. Roomy Spaces - The toddler fleece sleep sack offer ample room for kicking but can not be kicked off. This can promotes baby's healthy hip development, while the sleeveless design reduces the risk of overheating, ensures free arm movement, and provides lasting warmth for your little one. 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