This layer adds breathability for a safer, healthier and more hygienic design. The cover features a soft organic cotton surface and a 3-dimensional polyester lattice structure that creates a breathable space under the baby for increased airflow. This results in improved temperature regulation for less sweaty backs and a reduced risk of overheating. It also allows the baby to breathe directly through the cover if necessary. Get all the safety and comfort benefits of a breathable mattress with the convenience and practicality of a removable and washable cover.