The Stokke® Sleepi™ mattress offers optimal support for the child’s body, with a foam density of 35 kg/m3 and 40% compression at 3.7 kPa. The mattress used for the Sleepi™ Junior is somewhat thicker, as it is meant for use by older and therefore heavier children. The type of foam used in the mattresses (polyurethane) is widely used in mattresses and the product fully complies with the latest European safety standards for baby cribs. The Stokke® Sleepi™ provides a balanced ventilation system through the design of the mattress, mattress cover and bottom. To ensure optimal air circulation, the bottom side of the mattress has a wavy pattern specially designed to remove excess body heat. The bottom side of the mattress cover is made of a mesh material and the plywood base supporting it has large openings, which further enhance air circulation. Together, these features keep your baby cool and help prevent the growth of fungus.