The buttery soft sleep bag should be worn with a bodysuit or sleeper underneath. Designed to replace a loose blanket in the crib, please ensure this item fits snugly around the neck for safety. Two-way zipper allows for easy diaper changing and longer lengths allow room to grow. The premium bamboo viscose is smooth to the touch and has just the right amount of stretch. This breathable and hypoallergenic fabric will keep your little one cool in the summer and warm in the winter without irritating their sensitive skin. Ideal for room temperatures ranging from 69 - 73 °F (21-23 °C).