Memory foam mattress advantage
1)round shape
2) visco elastic foam base
3)roll compressed packing

memory foam mattress spec:
Originally developed by NASA to increase the comfort of Astronauts during lift-off, visco-elastic foam represents a quantum leap in bedding technology. The open-celled construction of Memory Foam creates a mattress system with a memory. It automatically senses your body weight and temperature, and then it responds by molding to your body's exact shape and position. This distributes your weight and reduces stress on your body's pressure points making sleep comfortable again.