... steel,Height 200mm Spring mattress structure & main materials1, using 72 # 6 ring big core high carbon steel, the height is: 160 mm ... , caliber: 7 cm, 6 ring, wire diameter 2.3 mm. Flyer sixty, wire diameter 1 ... .6 mm. A force spring 65, wire diameter 3 mm.2, ... flounce cotton: the 22 d high elastic sponge, thickness of 6 mm.