This mattress is very well constructed. I purchased the twin size for a daybed. It expanded to its full 10” height in less than 24 hours. There was no chemical smell from any off gassing. The only reason I didn’t give it 5 stars is that it is firmer than I expected. That being said, I have not slept on the mattress because it is being used in a guest bedroom. I received the mattress one day earlier than the expected arrival date. I am very happy and satisfied with the purchase. Best of all, for such a quality mattress the price was unbeatable!