What material is used for the inner cushion The mini crib mattress can be used on both sides to meet the needs of babies at different growth stages. Cooling Gel Memory Form Layer Cooling gel memory foam combines the advantages of memory foam and gel. The added gel factor reconciles the thermal insulation of conventional memory foam, making it more cooling; at the same time, the memory foam can evenly disperse body pressure, give the body even support, and enjoy a cool, zero-stress sleep/game time, suitable for growth middle child High Density Support Foam The solid side is hard and does not collapse, protecting the spine, suitable for babies. What\'s the size of the mini crib mattress? 38L x 24W x 3H inches,it fits only for the mini crib. Please measure your size before buying, this mattress does not fit standard cribs or pack \'n plays. What certification has the mattress passed The mattressmeets all safety standards set by CPSC/ASTM and passes by CertiPUR-US Certified Foam.It does not contain ozone depleting ingredients, formaldehyde, heavy metals (mercury, lead, etc.), polybrominated diphenyl ethers (PBDE), phthalates, volatile organic compounds. General Note: Please allow 24 - 72 hours for your Mattress to regain its full shape. Any memory foam will expand faster in a warmer room. In cold temperature, at delivery, your mattress may take a bit longer to return to full sized from its compressed state.The expansion time of the mattress will vary as per the surrounding.

• 2-Stage Dual Firmness: The mini crib mattress has dual firmness, it can provide support and comfort for your little ones at different stages of growth. The firm side is made of high density support fo