Our Serta® flat mattress foundation is a box spring alternative and is designed for long-lasting support and reduced motion for an indulgent night's sleep. Included: 1 Box Spring(s) Manufacturer Warranty: 10 Year Limited Bed Size: Twin Xl Measurements: 38 Width/Inches, 5.5 Height/Inches, 80 Length/Inches Maximum Weight Limit: 950 Lbs Base Material: 95% Wood, 5% Other 5% Or Less Care: Spot Clean Country of Origin: Made in US Mattress not included.