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  The Serta Flat Mattress Foundation is a 9" box spring alternative and provides the perfect support for your Serta mattress and is designed to provide durability and long-lasting comfort. Pairing this bed base with your mattress will support it and extend its life while helping isolate the effect of your partner’s movements in bed. Mattress Top Type: Tight Top Mattress Type: Innerspring Included: 1 Mattress(es), 1 Box Spring(s) Features: Cushioning Layer, Cooling Layer, Wrapped Coils, Foam Layer, Full Support Additional Information: Conforms To Body, Relieves Pressure Points, Eliminates Motion Transfer, Suitable for Adjustable Bed Frames Coil Count: 324 Coils Manufacturer Warranty: 10 Year Limited Bed Size: Twin Measurements: 38 Width/Inches, 11.5 Height/Inches, 74.5 Length/Inches Maximum Weight Limit: 850 Lbs Base Material: 70% Polyurethane, 30% Metal Comfort Type: Medium Mattress + Box Spring Measurements: 74.5 Length/Inches, 38 Width/Inches, 20.5 Height/Inches Care: Spot Clean Certifications And Listings: Certipur-Us Certified Mattress Height: 11.5" Country of Origin: Made in US Set includes mattress plus box spring/foundation. King and Cal. King mattress sets feature 2-piece side-by-side foundations for easier navigation in tight spaces.