Sleep SackOur snuggly soft sleep sack is a safer alternative to blankets in the crib and can be worn over pajamas to keep your little one's warm and cozy. it's the perfect transition from using our swaddles. A side zipper makes for easy late night changes, and a hidden under arm snap on our larger size ensures a perfect fit as baby grows. This sleeping bag is 2. 2 TOG for winter warmth. Oeko Tex certified: this design is rigorously tested for harmful substances