This sleep sack meets safety certifications and will not bunch up slip over baby face or loosen during sleep. Ultra soft stretchy and breathable hypoallergenic organic cotton fabric provides baby secure and comfortable sleep for sensitive skin all night long without overheating. Choose full arm containment for complete startle suppression or the arms up design that lets babies self soothe by bringing hands near their face and you can open or close cuffs to protect from facial scratches and partially suppress startle reflex. The arms up design allows natural hand to mouth self soothing and arm freedom while the torso stays snugly wrapped reducing frustration from tight swaddling and helping transitioning babies sleep longer and more soundly. The loose around the hips design prevents hip dysplasia and allows natural leg movement and the two way zipper opens from top side and bottom for quick access to the diaper area while keeping baby upper body swaddled and warm. It is machine washable and made from high quality stretchy cotton.