spring, compression spring, torsion spring, extension spring 1) Wire Dia.: 0.01 - 12.0mm 2) ISO9001:2000; ISO14001:2004 U Spring, Compression Spring, Torsion Spring, Extension Spring,Tension Spring1. ... of material certification, Material chemical composition est report,specification inspect report,surface treatment4.Photoes of Springs U spring, compression spring, torsion spring, extension spring