We are specialized in all various of frustum scroll springs.Finish can do black oxide,zinc,power coating, ... Zhuji, Zhejiang ,China' leading compression, extension torsion and frustum scroll spring manufacturers and trampoline spring suppliers. 1). Diameter from 0.50~6.00mm.2 ... supplier to key manufacturers.5). Members of the Institute of Spring Technology.6). Whether you require one, one thousand or ...