---Best Gel Memory Foam: 1-Mattress is compressed and packaged in a box for shipping, allowing it to easily be delivered to your door and expand to its full lofty shape inside your home. 2-Mattress is made of CertiPUR-US Certified foam, without any harmful off-gassing and substances. 3-Please allow up to 72 hours after opening the mattress for any potential odor to dissipate and adjust to its final feel once the foam settles . ---CARE INSTRUCTIONS UPON RECEIPT: It is also a good idea to know the size and the height of your mattress ahead of time to make sure you are ordering the correct size. Keep in mind that you should combine the height of your bed frame, foundation, or adjustable bed base with the height of your mattress to get a gauge of the how tall your sleep system will be. Memory foam mattresses Memory Mattress Foam Mattress Memory foam mattresses mattresses Memory Mattress Foam Mattress Memory Foam Mattress Gel Memory Foam Mattress