Doctor approved. Scientifically tested and proven safer than any other crib bedding option. Maintain optimal airflow, critical to reducing CO2 levels within a crib. Keep limbs inside. No risk of suffocation or entanglement, as found with other options. Provides 24″ of protection for your baby’s head and body. Just zip on. Includes 38 Vertical Crib Liners. Luxurious minky navy on both sides. Fit any crib. Compress and stretch to fit all rail size: wide or skinny, short or long. Zip 2 Wonder Bumpers together to covers corners or wider slats. Coordinate perfectly with matching Teething Guards. Easy to wash.