I purchased this to put on a new and very firm rv mattress. My husband and I wanted some relief on our pressure points. This is a  firm mattress pad like we wanted but it still had enough 3" cushion to help our knees, shoulders and hips feel better. Once fully expanded it does not squish super easy like others I've purchased in the past. It took a good 48 hrs for the creases to come out and for it to get to full size after opening up, but we are in a pretty cold climate and the only space we had to lay it flat was the cooler temp garage. We did not notice any smells upon opening it in a small bedroom or when sleeping on it.So far so good, but we have slept on it one night. It is a nice quality zippered mattress pad that covers the high density foam. We did not sleep hot on it like with some memory foam. Seems like a good purchase so far.