... modern firm mattress with import high quality cotton fabric,coconut,springs and environmental comfort.1):Using high carbon manganese steel ... . 3):2.4MM carbon manganese steel 6 ring BONNEL springs,elastic-rich,ergonomic design,after the second heat treatment and ... put into the cantainer: 6):Warranty :a): Three years against manufacture defect.b): Fully insured against damage.c): Double stitch sewing ...