... certified factory Key Specifications/Special Features:Product Name: Compression SpringFeatures: Wire Diameter: 0.01 to 20mm; ... steel, spring steel, alloy spring steel, refractory steel, high temperature resisting alloy, corrosion-resistant alloy, brass, and ... grinding and shot peening machineryPrecise tensile strength testers, compression testers, endurance testers, and magnetic powder flaw detectors ...