... 3 coloured zinc plated 4 ISO9001:2000,ROHS 5 Automotive,machine 1. MaterialCarbon steel, Spring steel, Stainless steel, Alloy steel, ... rust oil4. CertificationISO9001 Certificate, RoHS5. ApplicationsExtensively used for industrial machinery,model springAutomotive, medical device, agricultural machinery ,electronics, toy6. PackingInner ... or as per customers' requirements Compression Spring for Machine