Regal Pillow Top MattressSpring System: 630 Independent coils are entirely independent of each other allowing for added contour and pressure point relief to the mattress. The coils are pre compressed creating a firm surface making the unit more responsive to body movements. The coils are heat treated stress relieved wire that holds its shape and provides durable, consistent sleeping surface This spring sleeps 28% cooler than foam beds. Edge Support: Edge to Edge independent