Direct factory supply of eco-friendly copper spot-welding bolts and碰焊 screws: SUS welding stud M3*L, SUS welding stud M4*L, SUS welding stud M5*L, SUS welding stud M6*L, Aluminum welding stud M3*L, Aluminum welding stud M4*L, Aluminum welding stud M5*L, Aluminum welding stud M6*L, Copper-plated welding stud M3*L, Copper-plated welding stud M4*L, Copper-plated welding stud M5*L, Copper-plated welding stud M6*L, and other specifications. Shenzhen Hengbo Precision Hardware Products Co., Ltd.