The Serta Perfect Sleeper Medium Mattress delivers cooling comfort and dependable support for more restful sleep. At its core, the Q4 Support System-860 4-in-1 coils with BestEdge foam encasement-provides even weight distribution, stable support, and helps prevent sagging over time. Gel memory foam supports your lower back to help promote spinal alignment and pressure relief, making this mattress ideal for back sleepers and combination sleepers. Zoned support cushions pressure points like shoulders and hips while keeping the rest of your body comfortably supported. PillowSoft Aire foam adds gentle cushioning and airflow, while CoolTwist Gel Foam provides cooling comfort and helps pull heat away for a refreshing night’s sleep. Finished with a breathable wool layer and CoolFeel Fabric, this mattress helps prevent overheating, so you stay comfortable throughout the night. The Perfect Sleeper delivers reliable support, cooling comfort, and lasting performance -night after night. Serta StabL-Base 9" foundations provide the perfect support for your Serta mattress and are designed to provide durability and long-lasting comfort. Pairing the matching foundation to your Serta mattress will support it for the life of your mattress and help isolate the effect of your partner's movements. Serta StabL-Base foundations meet or exceed Federal Fire Retardancy Standards when used with a compatible Serta mattress. Set includes mattress plus box spring/foundation/base. Larger size mattress sets may feature 2-piece side-by-side foundations for easier navigation in tight spaces.