0.4mm nickel strip/ steel strip (MAX), 0.2mm copper sheet laminated with nickel strip (MAX), 0.25mm pure nickel strip (MAX). Total welding pen length: 45cm. 12V automotive battery (20AH-75AH), automotive jump starter (starting booster), 2-4S high-rate LiFePO4/Li-NIOB batteries, 2-3S superfarad capacitors.
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