It’s not gel memory foam if that is what you seek. It popped up searching for firm memory foam toppers though which is odd (but so did latex). I see this is my error also since memory foam is not stated in the description just gel foam, but noticed the box just said HD foam before opening. 

Update I decided to keep and try it out due to return costs. Actually exactly what I needed. It’s firm and helps even out my pillow top with sink holes that caused me a lot of pain and the warranty process is taking too long. I’m just gonna throw a 1” memory foam topper on top to get a little softness but otherwise I definitely recommend if mattress is too soft. I don’t think it’d help a too hard bed any. Since I always use a waterproof cover I can’t comment on smell or heat any. But it’s perfect for building your own solution to a problem bed. Thanks!