This Extra Plush Bamboo Top Mattress Pad compresses but does not develop a "memory", like memory foam, so it doesn't sag. It is approximately 1.5" to 2" thick. It's quilted so it's quite comfortable. When you lay on it, the loft compresses but does not collapse--meaning that it gives you softness and support, but none of the back-pain-inducing risks that I've experienced with thick memory foam mattresses and toppers. What I love the most is that this topper keeps us cool at night. It is definitely cooler and more breathable than memory foam. There is also no toxic scent. When it first arrived and I removed it from the packaging, there was a mild odor, but it faded before we slept on it that night. By contrast, memory foam always has a toxic chemical smell that never seems to entirely go away.