1,China Well-known Trademark 2, good ventilation system 3, appropriate hardness,comfortable 4, health care, 10years warranty Product feature1, combine our patent technology of balancing-net system and 5-zone spring system;2,apply the theory of human-engineering and mechanics;3,hollow inner structure, four air holes, good ventilation system, keep dry and clean;4,high-grade and deluxe brocade and ...