Zinus's Performance Plus Extra Firm mattresses are made with an additional 10% of iCoil support in the core of the mattress to provide motion separation for a comfortable night's sleep. Mattress layers include: 1 .5 in. top Comfort Foam layer, 2.5 in. High Density Foam Support layer. Only the highest quality foam-foam is CertiPUR-US Certified for durability, performance and content. The foam layers above the Support Plus iCoil Springs adjust to your body to give you a customized, comforting, sleep surface. The unique combination of Performance Plus iCoil Springs along with comforting foam layers will help you sleep well and wake up refreshed. Smartly shipped-our patented technology allows our mattresses to be efficiently compressed, rolled and shipped in a box conveniently to your door. Please open your mattress package within 72 hours of receipt and allow 48 hours for your new mattress to return to its original, plush shape. Worry-free 10-year limited warranty.