... diameter:2.4mmNumbr of coils:16materialcarbon steel,alloy spring steel,music wire steel,and stainless steel,iron ... ;etcsurface treament black oxide,Zinc/Nicke/Chrome plating,power coating,oiled to prevent rust,passivate,etc. User ... Compression springs, Extension springs, Torsion springs, Battery spring, Power spring, Coil spring , Leaf spring, Mould spring,etc., and other unique feature products. Your ...