Purchased this for the Fieldsboro Trundle Daybed we bought for our grandkids' playroom/bedroom for their overnight visits.  It was perfect thickness for the TOP of the bed.  Will purchase an 8" for the bottom.  It's a nice firmness.  Plan to air it out for about a week or more before placing any bedding on it, as their is a bit of a strange odor to it that takes some time to dissipate (that's why 4 stars).