It's a pretty hard mattress. It arrived vacuum sealed and rose to its full size as advertised in a day. I waited three days as recommended before trying it out. Try to size and impressive looking. It didn't feel like a cooling mattress though. Also, I had to put a pillow top overlay on this just to sleep, so whatever cooling effect it might have is covered. I'm really hoping this mattress will break in because I love the way it looks on my bed. I was excited to get it and admittedly a tad disappointed that's it's so hard my back hurt for a week. It is substantial and doesn't move much/at all, has good bounce back. I'm sleeping in my stomach on it and it is fairly comfortable. I can't return it so I will hope it improves with some wear. If you like a harder mattress you will really love this.