The pack and play mattress pad has a universal size 38x26 inches and fits most of standard size pack n play The tri-fold design makes folding up and packing into the included travel bag incredibly easy. The pack n play mattresses is made of premium foam making babies more comfortable when sleeping. In addition, it could help air flow and reduce body heat. The superior pack and play mattress could give your newborn, infant, baby and toddler a sweet dream The round corner design allows the mattress to be snugly connected with the corners of the pack n play without leaving any gaps