Experience the trusted comfort of Serta with Serta® Classic®. Featuring a soft, breathable cover, Pillowsoft® Aire Foam, and an 800-density coil support system, this mattress helps you sleep comfortably and wake ready to ease into your day. With 3 zones for lower back support, plus a gel memory foam upgrade for even more pressure relief, this mattress balances cool breathability with responsive support and pressure relief for a classically comfortable rest. Medium - perfect for all sleepers-side, back, stomach or combination sleepers. Breathable cover a soft, breathable cover helps you rest and wake refreshed. 3 zoned body support offers 3 separate zones to provide lower back support for Classic comfort. A breathable memory foam helps enhance airflow and heat dissipation for a feeling that can only be described as a cool, contouring type of comfort. This 800-coil density system provides contouring, cradling support and minimizes motion transfer. Certipur-US® Certified. Designed and built in USA. Adjustable friendly. 10 year warranty  Mattress Top Type: Tight Top Mattress Type: Innerspring Included: 1 Mattress(es) Features: Cooling Layer, Cushioning Layer, Foam Layer, Wrapped Coils, Full Support Additional Information: Eliminates Motion Transfer, Relieves Pressure Points, Suitable for Adjustable Bed Frames, Conforms To Body Coil Count: 324 Coils Manufacturer Warranty: 10 Year Limited Bed Size: Twin Measurements: 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 Mattress Height: 11.5" Country of Origin: Made in US Includes mattress only. Mattress plus box spring option also available.