I suggest you buy a mountain palm mattress, preferably a rattan mattress, which is made by hand, not by machine, but by adhesive, hand-made, pure natural, and does not contain any chemicals. You can go to Taobao to see Wangjiteng mattress, which is handmade, green, healthy and moderate in hardness, especially suitable for low back pain caused by disc herniation, children and the elderly during their growth and development. Now it's a 9-0 compromise. If you can read the materials clearly, it will be very hard all your life.