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 models Medium - 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 comfort Available 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 Top Mattress Type: Hybrid, Mattress In A Box Included: 1 Mattress(es) Features: Mattress In A Box, Foam Layer, Cooling Layer, Cushioning Layer, Wrapped Coils, Full Support Additional Information: Eliminates Motion Transfer, Conforms To Body, Suitable for Adjustable Bed Frames, Relieves Pressure Points Coil Count: 476 Coils Manufacturer Warranty: 10 Year Limited Bed Size: Twin Measurements: 38 Width/Inches, 9.5 Height/Inches, 74.5 Length/Inches Maximum Weight Limit: 850 Lbs Base Material: 70% Polyurethane, 30% Metal Comfort Type: Medium Care: Spot Clean Certifications And Listings: Certipur-Us Certified Country of Origin: Made in US Mattress arrives compressed in a box and then regains its size and shape after opening.