Our Cozy Dreams Sleep Sack is perfect for nighttime use by your little one in chilly weather. Place the sleep sack over their pajamas to help keep them warm and cozy at night without the risk of having a blanket covering their face. Our sleep sack zips from the feet up and features a snap tab to cover up the zipper pull. The Cozy Dreams Sleep Sack features PolarTec 100, which is lighter and stretchier than regular fleece. This option is good for children who sleep in cooler rooms paired with knit pajamas, or for really chilly temperatures - fleece pajamas.