1.Mattress spring made from high tensile steel wire. 2.Keep elastic,durable. 3.Competitive advantage price. Mattress spring details:Product Numbers:DTH-036Product details: Zoned pocket system is designed by human's shape. It divides the mattress into sections, giving different support levels in certain areas:head ,neck,shoulder,back,hip,legs,and feet.When every part of your body fit to the right ...