The Serta® Sheer Slumber 8-inch medium firm gel memory foam mattress in a box delivers quality, convenient comfort to your front door in our smallest carton ever. We've combined cooling gel memory foam with our durable Serta® Foam Core for a cool, supportive mattress that keeps you in dreamland all night long. And the best part? This mattress isn't just for grown-ups. Tested for kids and guest rooms, Sheer Slumber is bound to land in any room you need. With easy setup, CertiPUR-US-certified foams, and a 10-year limited warranty, you and your whole family can sleep soundly knowing that this mattress has got your back.