Steel wire 1.4-2.3mm / 6 ring tensile Strength: 1800-1900Mpa, 100000 durability test
High density foam is more than 27kg / M3. In general, 27kg / M3 foam is considered to be a comfortable support for human body and compressing rolled up packaging.
The lightweight foam do not have enough support strength which will return to its original shape in a few months, or cannot normally stretch.
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