Bought this futon mattress to replace the old futon mattress that replaced the worn out cushions (which replaced another set of worn out cushions) on my This End Up sofa. I'm a little disappointed in the thickness. Even after letting it "breathe" for a few days, the thickest part only measures 5.5 inches. It's still comfortable, so not worth the hassle of returning, but something to be mindful of.