Material : Spring steel.stainless steel size.available 8mm-100mm Disc spring,belleville ring,cup spring belleville ring,belleville spring,cup springMaterialSizeFinishSpring steel8mm-250mmPlainSS (A2)8mm-250mmBlackSS (A4)8mm-250mmphosphating We carry out DIN 2093 and GB/T 1972-2005 standards and our enterprise standard.