Really love it! Received in very good condition within just a few days from purchase.  We have an extra-extra firm queen mattress and our limbs would sometimes go numb if we laid on our side for too long. It also made my lower back hurt when I lay on my back for long -- (the mattress was a gift from my dad). Rather than buying a new mattress, we tried purchasing one of these instead for a fraction of the price.  I'll have to say my husband and I both have a hard time getting out of bed now, it's like sleeping on a soft cloud! It is definitely 4" thick (maybe even a little more), and the edges reach all the edges of the bed (sometimes foam toppers are slightly smaller than bed sizes, not this one!). The topper does not sag much getting in and out of bed, won't roll/disturb the other sleeper.  Very happy!  Hope it holds up for years to come.