... Material:403,201,202,304,304HC,304L,310S,316,316L,317L Surface:bright,polished,black Certificate:ISO,SGS Origin:China spring steel ... features:1, spring steel Size : all size is available.Base on ... mm--58 mm 2 spring steel Application: used for mattresses 3,spring steel Characteristic: 100% one wire splice free spring series, this kind ...