... zinc plated 4 ISO9001:2000,ROHS 5 long extension spring be made 1. MaterialCarbon steel, Spring steel, Stainless steel, Alloy steel, Oil ... cataphoresis,anti-rust oil4. CertificationISO9001 Certificate, RoHS5. ApplicationsThe long extension spring is extensively used for industrial machinery,model springAutomotive, medical device ... outer cartons or as per customers' requirements Long Extension Spring