Housed in their own cloth sleeves, pocket springs are small in diameter compared to open coils and are totally independent of any neighbouring springs. Not affected by varying weights and body shapes, the springs contour your shape perfectly, providing piston-like support to each part of the body. A flat rod-edge metal frame is fitted to the perimeter to ensure the integrity of the nested pocket springs and allow you the full use of the mattress width. Medium To Firm Mattress - Mattress Depth Approx. (27cm) To enhance its support, comfort and longevity, we recommend that you rotate the mattress from head to toe and it flip over on a regular basis.