All Perlimpinpin sleep bags are tested by independent laboratories and testing facilities to offer a safe and perfect solution for baby's sleep. Perfectly adjusted to fit the neck hole and opens only from the bottom, ensuring the bag is never over baby's head. The jersey knit fabric made of 70% viscose from bamboo and 30% cotton is ideal for babies with allergies and eczema. Enough bamboo to keep the properties of this unique fiber and just enough cotton to increase its durability. Baby's comfort is guaranteed!