1,OEM torsion spring 2,Stainless Steel 3,produce as your require 4,max 4mm diameter 5,Can coating with Zn etc All spring can be customized.torsion spring,spring roll,spring loaded in,torsion wire spring,slinky spring,gas spring arm,spring plunger,spring hose,diaphragm spring clutch,flat torsion spring,galvanized tension springAll spring produce as your require.rates and compress length,low ...