Casper engineers have layered Zoned Support™ memory foam over a foundation of spring coils for a hybrid mattress with superior comfort and support. Softer under the shoulders and firmer under the hips, waist and lower back, the mattress promotes superb comfort and improved spinal alignment. Open-cell foams have tiny pores to let excess hot air escape so you can stay cool, and they work together with three additional foam layers (high-density memory foam, zoned transition foam and durable support foam) to enable a perfect night's rest. Encased spring coils make changing positions easier while supporting Casper's zoned layers of memory foam.