I have a memory foam mattress that I bought from Wayfair a year or so ago. It was medium in terms of firmness and absolutely love it. This past 6 months I've been having hip problems and it was suggested I get a softer pad for my mattress. I bought this one because it was plush in terms of firmness. I love it. I seems to be bigger than 3" and if you have a high bed already this will add to the height, so keep that in mind. We are lucky enough to have a low line box spring so this didn't make our bed overly high (especially as we are height challenged!). If you are looking to soften up a firm mattress this is the way to go. It was priced right, got here in two days, and adds just enough softness to the bed, rather like a pillow top mattress. I would add a photo, but have already made the bed and don't want to take it all apart. I did put it under my mattress pad. It plumped up pretty quickly and there was no discernible odor.