... normal sizes are ok Features: Spring Tempered steel Die Springs A:spring specification: 1.spring Material:steel music wire (for ... heat resistance), or stainless steel (for corrosion resistance). 2.spring Finish: black oxide,white zinc, black zinc, colour zinc, ... C. Quality control sustems 1.Quality Certificate: ISO9001:2008, ISO14001:20042. Inspection quality system: ISO standard, 100% Whole range ...