Orthopedic mattress DEAL with bonnell spring system, 416 BONNELL springs in 120×200 dimensions. The springs are made of high-carbon steel. Multi-layer foam materials on both sides of the mattress provide the ideal conditions for a restful and rejuvenating sleep. High-density foam around the perimeter of the mattress ensures support and stability. All materials are anti-allergic & hypoallergenic. Reinforcing foam around the perimeter prevents mattress deformation. Handles for easy mattress rotation at regular intervals.