Breathable: This 100% cotton thread on the outside which keeps the cool air in the winter and the warm air in the summer. Concave-Design: The middle piece is concave to help give your little one the perfect head form letting their head comfortably fit in there, which also helps avoid vertebra twisting.Helps prevent baby's head from slumping during nap time,and protects baby's head releasing shaking. Unique shaped design is the best support for baby,support your baby's head and neck in ultimate comfort. This pillow is lightweight and portable,you can use it whenever you baby is laying down, for use in baby's car seat, swing, stroller, crib and more. This pillow made of soft fabric and 100% organic pp cotton,soft and gentle on baby skin, padded for comfort.It will make your baby feel comfortable and sleep well. Machine Washable,the whole pillow can be washed in machine((30℃ / 86℉).suitable all the season.