The appearance is beautiful and clean, and the heat dissipation is fast. It is suitable for assembling battery packs. All the brass bars are cleaned and protected by strong acid to ensure the brightness of the brass bars. 18650 battery spot welder pen, suitable for long‑term work, improve work efficiency, made of thick brass bar. This spot welder pen is suitable for industrial spot welding, convenient, and strong. This spot welding pen comes standard with a pair of Japanese concentric ball-point needles, which is effective. The handle of this spot welding pen has double springs to expand and contract, both of which can be independently expanded and contracted with moderate force control.