... years' experience;3. Imported fully-automatic precision compression spring manufacture facilities.4. Imported materials5. 10 year experience ... producing springs6. OEM/ODM service7. competitive price coil spring' s specification:Wire diameter0.1mm - 4mmLength3mm-200mmSurfacing coatingNickel ... steel, iron, etc.6. Surface coating: zinc,gold,silver,copper,dacro,black oxide, static spraying plastic, etc. 7 ...