RESTORATIVE SLEEP: Hybrid design constructed with added foam layers and individually encased coils to deliver greater pressure point relief and responsiveness. After a three month study, the American Chiropractic Association (ACA) found that this luxe design reduces spinal stress, improves lumbar support, and alleviates back pain. CUSTOMIZABLE FIRMNESS: If your extra firm mattress feels too firm, simply flip the mattress to achieve a medium-firm feel. Flip for firm or firmest—the choice is yours. (Plus, the flippable design improves the longevity of the mattress.) This is the preferred option for customers with sleep partners to ensure a more comfortable sleep experience. BREATHABLE MATERIALS: Fall sleep and stay asleep with foams that sport open cell technology to wick away excess body heat. Cooling upgrade available for hot sleepers. FIRMEST HYBRID MATTRESS ON THE MARKET: Never feel your back dip and never opt for the floor again. This 13.25 inch hybrid mattress offers extra firm support (a ten on the firmness scale) and will keep you firmly supported all night long. Designed to support up to 950 lbs. CERTIFIED SAFE MATERIALS: This bed in a box mattress is Fiberglass-free, GREENGUARD Gold certified, and made with CertiPUR-US foams. Each mattress is carefully assembled in our own Arizona facility and delivered right to your door. We want you to be happy with your mattress and that's why we offer a 120 night sleep trial. This dual sided ultra firm mattress allows you to choose between the firmest sleep experience available, or a medium-firm sleep experience. The choice is yours with just a flip of your mattress. This sleep surface is inspired by the minimalist approach to sleep found in places like East Asia, while including a more modern mattress design. Enjoy relief from back pain with a sleep surface that helps you achieve a neutral spine while also aiding proper blood circulation and better oxygen intake. The firmest mattress available, guaranteed. (Available with an optional sewn-on cooling cover from high tech PE fibers.)