Changing the sheets on a crib mattress can be a challenge. The Super Lightweight Crib Mattress makes changing the sheets a breeze! At 7 lbs, you can get the job done easily, so it's no hassle to give your baby a clean crib. Waterproof + Seamless edges Lullaby Earth crib mattresses are truly waterproof (unlike many "water resistant" models). They are even waterproof on the edges where most crib mattresses have seams. Just wipe up any mess with regular soap and water and you are good to go! A waterproof mattress makes for a more hygienic crib environment. By keeping fluids out of the mattress, there is a lower likelihood of mold or mildew growth. The waterproof surface doubly functions as a dust mite / bed bug barrier and is so pure that it even meets food contact standards! Firm Support Firmness is one of the most important features in a crib mattress. A soft crib mattress can sag, making it much more difficult for babies to shift positions or roll over if they are uncomfortable or having trouble breathing. In addition to a firm design, strong side and edge support adds structural stability, making the Lullaby Earth mattress an excellent choice for toddler beds.