The LifeNest Coversheets for the LifeNest Sleeping System are zippered sheets designed for your baby"s safety in mind. These are designed just for the LifeNest Sleeping System which is a highly breathable sleeping and ergonomic sleep positioner for babies. LifeNest is the most unique sleeping system since the invention of the mattress itself! • Main 3D spacer mesh fabric • 2 additional lateral mesh fabrics for ventilation channels • 4 ribbons to secure the mattress to the crib slats • 1 Lead free double slider YKK zipper • Available in 3 different colors: White, Pink, Blue