Designed with cooling gel memory foam, this mattress seamlessly blends value and convenience with the durability and trusted comfort Serta is known for. This collection offers all-foam and hybrid designs with 3 zones for lower back support and breathable fabric, so you wake up refreshed. Serta® Mattress-in-a-Box collection delivers comfort at a value with convenient delivery—so you can rest easy night after night.Only available in select modelsMedium - Perfect for all sleepers-side, back, stomach or combination sleepers.Convenient Delivery: Restful sleep delivered to your door—just unbox, unroll, and unwind.Breathable Fabric - A soft, breathable cover helps you rest and wake refreshed.3 Support Zones - zones provide lower back support for classic comfortAvailable in select models only.Cool Twist® Gel Memory Foam - Cooling gel swirled into premium memory foam offers enhanced airflow, heat dissipation, and contouring comfort.800 Edition Custom Support Coil System - Durable, 800-density individually-wrapped coils keep you supported throughout the night.Assembled in USA.Adjustable Base Compatible Mattress Top Type: Tight TopMattress Type: Mattress In A Box, HybridIncluded: 1 Mattress(es)Features: Mattress In A Box, Cushioning Layer, Wrapped Coils, Full Support, Cooling Layer, Foam LayerAdditional Information: Eliminates Motion Transfer, Relieves Pressure Points, Conforms To Body, Suitable for Adjustable Bed FramesCoil Count: 476 CoilsManufacturer Warranty: 10 Year LimitedBed Size: TwinMeasurements: 38 Width/Inches, 9.5 Height/Inches, 74.5 Length/InchesMaximum Weight Limit: 850 LbsBase Material: 70% Polyurethane, 30% MetalComfort Type: MediumCare: Spot CleanCertifications And Listings: Certipur-Us CertifiedCountry of Origin: Made in US Mattress arrives compressed in a box and then regains its size and shape after opening. Serta Classic™ 12" Medium Hybrid Mattress a Box