Polyester #1 BRAND INDEPENDENTLY TESTED FOR SAFETY: From BreathableBaby, the original, patented breathable mesh liner with millions sold since 2002. Designed for crib styles sold in the North American marketplace and tested by a third party CPSC-accepted accredited lab to meet or exceed ASTM F1917 Standard Consumer Safety Performance Specification for Infant Bedding and Related Accessories. Never use a mesh liner that is not compliant with ASTM F1917. Non-compliant products may present safety hazards. HELPS PREVENT ENTRAPMENT: Unlike padded bumpers, our mesh liners keep little limbs safely inside without the risk of restricted airflow. And, also provide a visual shield to help provide a more peaceful night\u2019s sleep. Not to mention, they keep pacifiers inside and within reach! ESSENTIAL AIRFLOW MESH WITH MICROFIBER TRIM: Constructed from a single-layer of Airflow Mesh (2 mm thick) for basic function. Light blocking rating of >60%. Made of 100% polyester mesh exclusive of decoration. 0.75\u201dH (1.9 cm) microfiber trim along top and bottom edges. Attaches with ties as well as hook and loop for extra security. Contains no harmful chemicals, flame retardants or formaldehyde. FITS FULL-SIZE FOUR-SIDED SLATTED AND SOLID BACK CRIBS: 1 long panel 9\u201dH x 111\u201dL (23 cm x 282 cm) and 1 short panel 9\u201dH x 82\u201dL (23 cm x 208 cm). Designed with our exclusive No-Gap-Wrap to ensure maximum coverage. Does not fit cribs with attached changing tables, solid end cribs, portable/mini cribs, or cradles. For use on full-size cribs only. EASY TO INSTALL: Smartly adjusts to fit. Always install the bottom edge 1\u201d (2.54 cm) below the top of the mattress and secure all fastenings. If the liner does not feel taut or is sagging, review the instruction manual, watch the installation video, or contact customer care for help. Or try a Classic or Deluxe mesh liner, which have stiffer meshes and fit some cribs styles better.