We unpacked it and let it air out for a day in a side room. There was slight gassy smell but it was gone after a day. The combo of the foam and thick filled pad is about 4" and is very, very comfortable.. it almost feels like you are laying on a large pillow, but without the lumps you would get as the foam conforms to your body pressure points. The only complaint I have is that it doesn't dissipate heat from your body very well. Where you are lying it feels hot under you. It's not a deal breaker, but if you live in a hot climate it might be uncomfortable.