I'ts a mattress topper,the washable bedding goes on top. When was the last time you washed a mattress for instance? As a" menopausal,bone thinning and causing pain just lying in bed" female...my sleeping life has been changed dramatically ,by a memory foam mattress!!No more towels to get a softer place in the bed! I can lie comfortably ,generally ,in any position i want:-) I'm in heaven now ...please do the good thing !!