95% Cotton Comfortable Material : The Swaddle sack made of 95% Cotton and 5% Elastane.feeling snug fit from our stretch fabric.creates a familiar and secure feeling,just like in the womb to calm the moro reflex. Double Zipper Design : Our double zipper design can effectively protect the delicate body of the baby, and it is convenient for parents to change the diaper or wipe the cream and apply body lotion for the baby.