Closure Type Pull On GEL MEMORY FOAM MATERIAL: Our memory foam mattress topper readily conforms to the curves and shape of your body, distributes weight evenly to alleviate pressure points for better sleep. MORE COMFORTABLE SLEEP: The gel memory foam material used in our mattresses reduces heat and improves the airflow to refresh the gas permeability; add to the mattress for custom comfort. SOFT BUT NOT FOLDABLE: our mattress is soft, do not roll up and store too long after opening, and do not put items on top, which will increase the risk of tearing. CertiPUR-US CERTIFIED: Our Gel Swirl memory foam topper is made of CertiPUR-US certified materials. The Gel Swirl memory foam topper meets or exceeds standards for content, emissions, and durability. BEFORE FIRST USE: leave the memory foam flatly in a well ventilated area for 48-72 hours until it’s fully expanded.