1)Plastic material: PA66,GF 15%,UL 94-HB; temperature-resistant:130癈 2)Metal material: spring steel, nickel-plated; 3)Characteristic: good elasticity; The spring unit pressure length is 3.8mm, its pressure force should more than 0,40Kgf; The spring unit pressure length is 4.4mm, its pressure force should more than 0.5Kgf.