I bought this in the hopes of "rejuvenating" and older mattress ,which I had which was still in good condition, but which needed some cushioning. Upon gently removing the mattress topper from it's packaging, I gave it the necessary time to unravel itself (less than an hour)and air out (about a week). Once I put it onto my full sized bed, I found that it fit perfectly and the mattress which came with it fit well to keep things in place. I have slept on it just to try it out as it is in my guest bedroom and several guests have had the opportunity to try it and the consensus is that it is comfortable and supportive. Seems like a good purchase so far!