?Medi Spine (Pocket Spring) is our best seller. The mattress has been recommend by chiropractor because of it's Extra Firm Pocket Spring technology support system. These are included Thera Blue Cell & Thera High Pressure PU Foam Layer. Those system will help you to fix problem?for those two have back problems and need extra 3 cm spiral system to support and comfort your back while you sleep. Pocketed Spring Thera Blue Cell Thera Cotton Layer Thera Webbing Thera High Pressure Foam Zipper Model / Washabel Cover Foam Encasmed 2 Tone Color.Mattress Thickness : 30 cm