Serta Nickelodeon Collection by Dora and Diego Memory Foam Mattress, Twin Fun, colorful cover featuring likenesses of Nickelodeon's most popular cartoon characters- Dora the Explorer, Go, Diego, Go, and SpongeBob SquarePants 2-Inch of serta's space age visco-elastic memory foam rest on top of a hi-density foam core to provide superior comfort at the sleep surface Visco-elastic memory foam gently conforms to your body and contours to your sleeping position As your child's body is surrounded in cradling comfort, the memory foam helps to reduce pressure points that can cause your child to toss and turn, wake up and shift positions The result is an extremely comfortable and more restful sleep