What is the formula for our best-selling mattress? Precisely layered CertiPUR American certified foam can let you fit into this mattress properly. Our mattress is a perfect combination of soft memory foam and ultra dense base foam, which can provide a sense of support when shaping your body, supporting your most developed joints and aligning your spine. In addition, this mattress uses our high-quality high-density bottom foam to prevent any uncomfortable sinking, sagging or turning over in bed, so as to ensure that you can get the ideal support level and get a peaceful sleep.