It is basically a piece of foam wrapped in plastic with "fancy" pattern on it. Very light, very soft, no support at all.  It does not feel like a mattress, rather thicker mattress pad. My baby is 6 months old now so doesn't weight much, but I can't picture her being comfortable on that "mattress" in few months. Buying something else - this one will be a dog's bed - at least its waterproof.